Limewire doesn't contain any spyware, but any of them will allow you to download viruses that other people share. Tell him to scan whatever he downloads with a virus scanner. Common sense wouldn't hurt either.
shareaza?... its so so... last time i checked it didnt stand a chance against emule or utorrent (which -in my opinion- are the best, bman... no bundled spyware or anything and both very reliable to use)
if your friend isnt too into computers, tell him to get a good av with good real time scan and to be careful with what he downloads... maybe google some newbie p2p guides