I just looked through my SSH logs:
Jan 3 16:25:07 derek sshd[20552]: Failed password for invalid user staff from 61.232.12.74 port 47970 ssh2
Jan 3 16:25:12 derek sshd[20554]: Failed password for invalid user sales from 61.232.12.74 port 56057 ssh2
Jan 3 16:25:19 derek sshd[20556]: Failed password for invalid user recruit from 61.232.12.74 port 34721 ssh2
Jan 3 16:25:23 derek sshd[20560]: Failed password for invalid user alias from 61.232.12.74 port 47259 ssh2
Jan 3 16:25:29 derek sshd[20562]: Failed password for invalid user office from 61.232.12.74 port 54685 ssh2
Jan 3 16:25:34 derek sshd[20566]: Failed password for invalid user samba from 61.232.12.74 port 35611 ssh2
Jan 3 16:25:40 derek sshd[20568]: Failed password for invalid user tomcat from 61.232.12.74 port 43391 ssh2
Jan 3 16:25:44 derek sshd[20570]: Failed password for invalid user webadmin from 61.232.12.74 port 54398 ssh2
Jan 3 16:25:50 derek sshd[20574]: Failed password for invalid user spam from 61.232.12.74 port 34716 ssh2
Jan 3 16:25:55 derek sshd[20576]: Failed password for invalid user virus from 61.232.12.74 port 44590 ssh2
Jan 3 16:26:00 derek sshd[20578]: Failed password for invalid user cyrus from 61.232.12.74 port 53034 ssh2
Jan 3 16:26:05 derek sshd[20582]: Failed password for invalid user oracle from 61.232.12.74 port 33049 ssh2
Jan 3 16:26:10 derek sshd[20584]: Failed password for invalid user michael from 61.232.12.74 port 41657 ssh2
Jan 3 16:26:15 derek sshd[20586]: Failed password for invalid user ftp from 61.232.12.74 port 49626 ssh2
Jan 3 16:26:20 derek sshd[20588]: Failed password for invalid user test from 61.232.12.74 port 58287 ssh2
Jan 3 16:26:26 derek sshd[20590]: Failed password for invalid user webmaster from 61.232.12.74 port 38132 ssh2
Jan 3 16:26:31 derek sshd[20592]: Failed password for invalid user postmaster from 61.232.12.74 port 47055 ssh2
Jan 3 16:26:37 derek sshd[20594]: Failed password for invalid user postfix from 61.232.12.74 port 55739 ssh2
Jan 3 16:26:42 derek sshd[20598]: Failed password for invalid user postgres from 61.232.12.74 port 37382 ssh2
Jan 3 16:26:47 derek sshd[20600]: Failed password for invalid user paul from 61.232.12.74 port 45001 ssh2
Jan 3 16:26:51 derek sshd[20604]: Failed password for root from 61.232.12.74 port 53053 ssh2
Jan 3 16:26:57 derek sshd[20608]: Failed password for invalid user guest from 61.232.12.74 port 33028 ssh2
Jan 3 16:27:02 derek sshd[20610]: Failed password for invalid user admin from 61.232.12.74 port 42385 ssh2
Jan 3 16:27:09 derek sshd[20612]: Failed password for invalid user linux from 61.232.12.74 port 51860 ssh2
Jan 3 16:27:14 derek sshd[20614]: Failed password for invalid user user from 61.232.12.74 port 34882 ssh2
Jan 3 16:27:19 derek sshd[20616]: Failed password for invalid user david from 61.232.12.74 port 43296 ssh2
Jan 3 16:27:25 derek sshd[20618]: Failed password for invalid user web from 61.232.12.74 port 52584 ssh2
Jan 3 16:27:30 derek sshd[20622]: Failed password for invalid user apache from 61.232.12.74 port 33583 ssh2
Jan 3 16:27:35 derek sshd[20626]: Failed password for invalid user pgsql from 61.232.12.74 port 42544 ssh2
Jan 3 16:27:42 derek sshd[20628]: Failed password for invalid user mysql from 61.232.12.74 port 52363 ssh2
Jan 3 16:27:47 derek sshd[20632]: Failed password for invalid user info from 61.232.12.74 port 36526 ssh2
Jan 3 16:27:55 derek sshd[20634]: Failed password for invalid user tony from 61.232.12.74 port 45554 ssh2
Jan 3 16:28:02 derek sshd[20638]: Failed password for invalid user core from 61.232.12.74 port 60180 ssh2
Jan 3 16:28:08 derek sshd[20640]: Failed password for invalid user newsletter from 61.232.12.74 port 43810 ssh2
Jan 3 16:28:14 derek sshd[20644]: Failed password for invalid user named from 61.232.12.74 port 53885 ssh2
Jan 3 16:28:19 derek sshd[20646]: Failed password for invalid user visitor from 61.232.12.74 port 34720 ssh2
Jan 3 16:28:28 derek sshd[20650]: Failed password for invalid user ftpuser from 61.232.12.74 port 43796 ssh2
Jan 3 16:28:34 derek sshd[20654]: Failed password for invalid user username from 61.232.12.74 port 58307 ssh2
Jan 3 16:28:39 derek sshd[20658]: Failed password for invalid user administrator from 61.232.12.74 port 40039 ssh2
Jan 3 16:28:45 derek sshd[20662]: Failed password for invalid user library from 61.232.12.74 port 49491 ssh2
Jan 3 16:28:51 derek sshd[20664]: Failed password for invalid user test from 61.232.12.74 port 60543 ssh2
Jan 3 16:28:56 derek sshd[20666]: Failed password for root from 61.232.12.74 port 42015 ssh2
Jan 3 16:29:02 derek sshd[20668]: Failed password for root from 61.232.12.74 port 51793 ssh2
Jan 3 16:29:08 derek sshd[20694]: Failed password for invalid user admin from 61.232.12.74 port 33110 ssh2
Jan 3 16:29:13 derek sshd[20698]: Failed password for invalid user guest from 61.232.12.74 port 43066 ssh2
Jan 3 16:29:22 derek sshd[20702]: Failed password for invalid user master from 61.232.12.74 port 53343 ssh2
Jan 3 16:29:27 derek sshd[20704]: Failed password for root from 61.232.12.74 port 39298 ssh2
Jan 3 16:29:36 derek sshd[20708]: Failed password for root from 61.232.12.74 port 50226 ssh2
Jan 3 16:29:42 derek sshd[20712]: Failed password for root from 61.232.12.74 port 38921 ssh2
Jan 3 16:29:48 derek sshd[20714]: Failed password for root from 61.232.12.74 port 48867 ssh2
Jan 3 16:29:55 derek sshd[20718]: Failed password for root from 61.232.12.74 port 60474 ssh2
Jan 3 16:30:00 derek sshd[20722]: Failed password for invalid user admin from 61.232.12.74 port 43873 ssh2
Jan 3 16:30:10 derek sshd[20726]: Failed password for invalid user admin from 61.232.12.74 port 53147 ssh2
Jan 3 16:30:15 derek sshd[20728]: Failed password for invalid user admin from 61.232.12.74 port 40931 ssh2
Jan 3 16:30:22 derek sshd[20730]: Failed password for invalid user admin from 61.232.12.74 port 50321 ssh2
Jan 3 16:30:28 derek sshd[20732]: Failed password for root from 61.232.12.74 port 60204 ssh2
Jan 3 16:30:33 derek sshd[20734]: Failed password for root from 61.232.12.74 port 42430 ssh2
Jan 3 16:30:40 derek sshd[20736]: Failed password for invalid user test from 61.232.12.74 port 52732 ssh2
Jan 3 16:30:46 derek sshd[20740]: Failed password for invalid user test from 61.232.12.74 port 36377 ssh2
Jan 3 16:30:58 derek sshd[20744]: Failed password for invalid user webmaster from 61.232.12.74 port 45941 ssh2
Jan 3 21:14:33 derek sshd[24073]: Failed password for invalid user staff from 61.142.83.245 port 48583 ssh2
Jan 4 04:51:49 derek sshd[27135]: Failed password for root from 125.248.86.5 port 44088 ssh2
Jan 4 04:51:55 derek sshd[27137]: Failed password for invalid user sifak from 125.248.86.5 port 48097 ssh2
Jan 4 04:52:01 derek sshd[27139]: Failed password for invalid user slasher from 125.248.86.5 port 52529 ssh2
Jan 4 04:52:08 derek sshd[27141]: Failed password for invalid user fluffy from 125.248.86.5 port 57174 ssh2
Jan 4 04:52:14 derek sshd[27143]: Failed password for invalid user admin from 125.248.86.5 port 34434 ssh2
Jan 4 04:52:19 derek sshd[27145]: Failed password for invalid user test from 125.248.86.5 port 38912 ssh2
Jan 4 04:52:24 derek sshd[27147]: Failed password for invalid user guest from 125.248.86.5 port 43622 ssh2
Jan 4 04:52:29 derek sshd[27149]: Failed password for invalid user webmaster from 125.248.86.5 port 47444 ssh2
Jan 4 04:52:37 derek sshd[27151]: Failed password for invalid user mysql from 125.248.86.5 port 51329 ssh2
Jan 4 04:52:42 derek sshd[27153]: Failed password for invalid user oracle from 125.248.86.5 port 56331 ssh2
Jan 4 04:52:47 derek sshd[27155]: Failed password for invalid user library from 125.248.86.5 port 60746 ssh2
Jan 4 04:52:56 derek sshd[27157]: Failed password for invalid user info from 125.248.86.5 port 36366 ssh2
Jan 4 04:53:01 derek sshd[27159]: Failed password for invalid user shell from 125.248.86.5 port 42826 ssh2
Jan 4 04:53:07 derek sshd[27161]: Failed password for invalid user linux from 125.248.86.5 port 46849 ssh2
Jan 4 04:53:14 derek sshd[27163]: Failed password for invalid user unix from 125.248.86.5 port 50759 ssh2
Jan 4 04:53:26 derek sshd[27165]: Failed password for invalid user webadmin from 125.248.86.5 port 54377 ssh2
Jan 5 18:41:07 derek sshd[18880]: Failed password for james from 127.0.0.1 port 40283 ssh2
EDIT:
I did a whois on the 61 address - It's the Chinese.
% [whois.apnic.net node-1]
% Whois data copyright terms
www.apnic.net/db/dbcopyright.htmlinetnum: 61.232.0.0 - 61.237.255.255
netname: CRTC
country: CN
descr: CHINA RAILWAY TELECOMMUNICATIONS CENTER
admin-c: LQ112-AP
tech-c: LM273-AP
status: ALLOCATED PORTABLE
changed: ipas@cnnic.net.cn 20030121
mnt-by: MAINT-CNNIC-AP
source: APNIC
person: LV QIANG
nic-hdl: LQ112-AP
e-mail: wangpei@chinatietong.com
address: 22F Yuetan Mansion,Xicheng District,Beijing,P.R.China
phone: +86-10-51892106
fax-no: +86-10-51890674
country: CN
changed: ipas@cnnic.net.cn 20060911
mnt-by: MAINT-CNNIC-AP
source: APNIC
person: liu min
nic-hdl: LM273-AP
e-mail: crnet_tec@chinatietong.com
address: 22F Yuetan Mansion,Xicheng District,Beijing,P.R.China
phone: +86-10-51848796
fax-no: +86-10-51842426
country: CN
changed: ipas@cnnic.net.cn 20041208
mnt-by: MAINT-CNNIC-AP
source: APNIC
inetnum: 61.232.0.0 - 61.237.255.255
netname: CRTC
country: CN
descr: CHINA RAILWAY TELECOMMUNICATIONS CENTER
admin-c: LQ112-CN
tech-c: LM273-CN
status: ALLOCATED PORTABLE
changed: ipas@cnnic.net.cn 20030121
mnt-by: MAINT-CNNIC-AP
source: CNNIC
person: LV QIANG
nic-hdl: LQ112-CN
e-mail: crnet_mgr@chinatietong.com
address: 22F Yuetan Mansion,Xicheng District,Beijing,P.R.China
phone: +86-10-51890499
fax-no: +86-10-51890674
country: CN
changed: ipas@cnnic.cn 20060419
mnt-by: MAINT-CNNIC-AP
source: CNNIC
person: liu min
nic-hdl: LM273-CN
e-mail: crnet_tec@chinatietong.com
address: 22F Yuetan Mansion,Xicheng District,Beijing,P.R.China
phone: +86-10-51848796
fax-no: +86-10-51842426
country: CN
changed: ipas@cnnic.net.cn 20041208
mnt-by: MAINT-CNNIC-AP
source: CNNIC