It's not very easy to get a virus on a P2P network as long as you have some common sense and a decent understanding of how computers (well, Windows especially, assuming that's what you're using) work.
Basically it's this: don't download applications (anything ending with a .exe extension)
and the rest of most files are usually obvious if they're viruses. In other words, don't download something called "britney spears pokemon xxx linkin park avril lavigne.gif". One time a friend had a filename kinda similar (well, the first half or so of what I just said was pretty accurate) and it caused his computer to freeze or something whenever he opened it.
EDIT: To answer the original question, like Zizzlepop said, it's possible but highly unlikely. Personally, I wouldn't worry about it unless you're planning on sharing the file (which, even then, isn't a HUGE threat unless you have a ton of files being shared illegally 24/7).