Without being perfectly sure, I would say that there is only one single p2p sharing app that is 100% safe (i think there is one for windows, but i don't remember what it's called)

The riaa hired a hacker group called gobbles to develop some sort of virus to infest p2p networks. Here is what gobbles said about the virus:

"Our software worked better than even we hoped, and current reports indicate that nearly 95% of all p2p-participating hosts are now infected with the software that we developed for the RIAA."

Kinda scary This is how it works, it's prolly just for windows though:

(sorry if the description under is weird, cos I had to translate it from Norwegian )

1. You download an infected file
2. When you play this in winamp (or mplayer, Windows Media Player, xine, mpql23, xmms etc.) all the p2p software on the local system (?) is infected
3. Media catalogs are indexed and the result is sent back to the riaa and saved.

I don't think any you are at risk unless you share a hell of a lot of files though. Also I live in Norway so I can't be touched by the RIAA or american law