Bearshare is the only client right now that has spyware in it. It uses Onflow which is a common spyware program that can be detected and removed by Ad-aware. Download this, its free. I think the Bearshare authors also released a program to remove the Onflow registry entries. Check their forum on that. You might want to check your other freeware progs at the link below. There are hundreds of spyware infested programs.

http://www.infoforce.qc.ca/spyware/enknownlistfrm.html

Lastly, read this:
http://www.senate.gov/~edwards/press/2000/oct05-pr.html

and support it...hopefully this legislation will make it through.