DiamondCS wrote a few different "Server Snipers." These are actually kind of old, but still useful. What this does is finds an certain trojan that has been installed on your system, and pulls out all the encrypted information (on some trojans). This inculdes setup information, IRC channels, ICQ numbers, passwords, etc etc. Very useful for finding out who sent you that particular trojan. It can also remove said trojan.
You can download the snipers for BO2K, Win.Trinoo, and SubSeven 2.1 from http://www.webattack.com/freeware/se...antihack.shtml near the bottom of the list.
There are a lot of other decent security programs there also, so take a look around.