Tor
I came across an interesting project by the EFF: it is called Tor. In essence it is a program that selects a random path through a set of special Tor proxies to make your identity hard to determine. I have managed to painlessly configure Gaim to use it for ICQ. One thing I noticed is that it took a bit longer to authenticate with the ICQ server - not sure if it slower because of someone somewhere having bad/congested connection or it is Tor taking time to set up the several proxy hops long (quite possibly 30 or more router hops) route.