I'm not sure which does what but if you install both of these apps (I think they are free) you can view many file types in QT and Safari like avi, wmv etc. that were a hassle before. I have not tested playing within Limewire but I bet if it plays on QT it will play in Limewire.

http://www.divx.com/divx/mac/
http://www.flip4mac.com/

Morgan