hmm - sounds like somebody out there has root access, you may have a nice new warez server on your desktop. If your box is that far gone, you'll have to restore from a known good backup after you format the disk(s).

You can also try things like a root kit finder - www.sourceforge.net has root kit hunter.

Generally unix is less prone to all the bad stuff out there so you must have been some interesting places. Be sure to at least use a firewall and maybe a nat on your router/dsl modem. PS: going to warez sites is not always a good idea