I write all (futile) login attempts on my site to a log file. I can confirm this rise in password bruteforcing attempts during the last days.

This is what the bruteforce passwords look like, these tried to login as "admin":

[Sat Apr 13 05:30:31 2013] nevalidniipass
[Sat Apr 13 05:30:34 2013] gfhjkm
[Sat Apr 13 05:30:37 2013] gggggggg
[Sat Apr 13 05:30:39 2013] ghbdtn
[Sat Apr 13 05:30:41 2013] ghgftmn6
[Sat Apr 13 05:30:43 2013] ghghgh
[Sat Apr 13 05:30:44 2013] ghjkju
[Sat Apr 13 05:30:46 2013] ghjrdjcn
[Sat Apr 13 05:30:48 2013] gjkzyjxr
[Sat Apr 13 05:30:50 2013] globax123
[Sat Apr 13 05:30:52 2013] go0gle
[Sat Apr 13 05:30:54 2013] go2fuck
[Sat Apr 13 05:30:55 2013] gogogo
[Sat Apr 13 05:30:57 2013] goldz
[Sat Apr 13 05:30:59 2013] gthtw112
[Sat Apr 13 05:31:02 2013] guest
[Sat Apr 13 05:31:05 2013] h69s9t
[Sat Apr 13 05:31:07 2013] hackett
[Sat Apr 13 05:31:08 2013] hal9000
[Sat Apr 13 05:31:10 2013] hazem200
[Sat Apr 13 05:31:12 2013] heccrbqh
[Sat Apr 13 05:31:14 2013] herbie
[Sat Apr 13 05:31:16 2013] hghgh
[Sat Apr 13 05:31:18 2013] hhhh1
[Sat Apr 13 05:31:20 2013] hhhhhaaaaa
[Sat Apr 13 05:31:21 2013] hockey
[Sat Apr 13 05:31:23 2013] home555
[Sat Apr 13 05:31:25 2013] honda
[Sat Apr 13 05:31:27 2013] htrdbtv
[Sat Apr 13 05:31:29 2013] http
[Sat Apr 13 05:31:31 2013] hycvibck
[Sat Apr 13 05:31:33 2013] i_am
[Sat Apr 13 05:31:35 2013] ib6ub9
[Sat Apr 13 05:31:37 2013] icing
[Sat Apr 13 05:31:38 2013] icq123
[Sat Apr 13 05:31:40 2013] icqpass
[Sat Apr 13 05:31:42 2013] if6was9
[Sat Apr 13 05:31:44 2013] ifhgtq79
[Sat Apr 13 05:31:46 2013] ifyfif
[Sat Apr 13 05:31:48 2013] iiiiiiii
[Sat Apr 13 05:31:50 2013] ikaihsot
[Sat Apr 13 05:31:52 2013] il0vey0u
[Sat Apr 13 05:31:54 2013] iloveaol
[Sat Apr 13 05:31:56 2013] iloveu
[Sat Apr 13 05:31:57 2013] iloveyou
[Sat Apr 13 05:31:59 2013] inferno
[Sat Apr 13 05:32:01 2013] infinity
[Sat Apr 13 05:32:05 2013] infree
[Sat Apr 13 05:32:08 2013] iof314
[Sat Apr 13 05:32:11 2013] jake4440
[Sat Apr 13 05:32:13 2013] jamie1
[Sat Apr 13 05:32:15 2013] janice
[Sat Apr 13 05:32:16 2013] jay18birdman
[Sat Apr 13 05:32:18 2013] jc5000
[Sat Apr 13 05:32:20 2013] jeffery
[Sat Apr 13 05:32:22 2013] john1
[Sat Apr 13 05:32:24 2013] joomla
[Sat Apr 13 05:32:26 2013] joshua
[Sat Apr 13 05:32:27 2013] keys
[Sat Apr 13 05:32:29 2013] kholmsk3
[Sat Apr 13 05:32:31 2013] kir11421
[Sat Apr 13 05:32:33 2013] kkkkkk
[Sat Apr 13 05:32:35 2013] kngvhpg
[Sat Apr 13 05:32:37 2013] ko#]|7sz
[Sat Apr 13 05:32:39 2013] kxvq4k2d
[Sat Apr 13 05:32:41 2013] laksmi
[Sat Apr 13 05:32:42 2013] lefty
[Sat Apr 13 05:32:44 2013] lex1977
[Sat Apr 13 05:32:46 2013] linux
[Sat Apr 13 05:32:48 2013] lol
[Sat Apr 13 05:32:50 2013] lol777
[Sat Apr 13 05:32:52 2013] lollol
[Sat Apr 13 05:32:54 2013] lovelove
[Sat Apr 13 05:32:55 2013] lucille2000
[Sat Apr 13 05:32:57 2013] lyxasgje
[Sat Apr 13 05:32:59 2013] m@$ter
[Sat Apr 13 05:33:02 2013] m@ster
[Sat Apr 13 05:33:07 2013] m1911a1
[Sat Apr 13 05:33:11 2013] google
[Sat Apr 13 05:33:13 2013] facebook
[Sat Apr 13 05:33:15 2013] microsoft
[Sat Apr 13 05:33:17 2013] obama
[Sat Apr 13 05:33:18 2013] twitter
[Sat Apr 13 05:33:20 2013] wp
[Sat Apr 13 05:33:22 2013] wordpress
[Sat Apr 13 05:33:24 2013] 060890
[Sat Apr 13 05:33:26 2013] 060891
[Sat Apr 13 05:33:28 2013] 060893
[Sat Apr 13 05:33:30 2013] 060988
[Sat Apr 13 05:33:32 2013] 060989

They also try to get access as "administrator".