OS X has many crashes for a variety of reasons, too much CPU usage, too much memory, etc. However, Jens Uwe-Mager (Jum) has made a version of Limewire for OS X that fixes these bugs and reduces CPU and memory usage. You can find the jum version here: http://baghira.han.de/~jum/ . Just click on the link that starts with limewire and follow the instructions from there.