You will also see many people recommending you change the default port from 22 to some high port number, but I'm not so sure that makes much of a difference.
By changing the ports on some of my producton machines, I reduced the incorrect login attempts in my log down from circa 8-10 000 per day to only as often as I mistype my RSA passphrase :)
At least this way I can seriously view my logs with a view to noticing something sinister.
B
I´ve got the same number of incorrect login in my log... and so I´ve changed the ports, just like you, adn the attack stopped... And so, now I am a sada guy, with no IP´s to have some fun.. (yes, I do usually do something with who attacks me, have even made a software to serch the logs and log all unique IP´s, and login attempts into a mysql table...) If tou likes to have fun, let the port 22 ,if don´t like to have fun with the logged ip´s, change the port!