KAZZA, NAPSTER, MORPHEUS, WINMX, IMESH, EDONKEY are all file sharing systems that allow people on the internet to post files that others can see and download. There are a couple of drawbacks to getting files this way:
1). It's a federal crime with a fine of up to $150,000 per copyrighted post.
2). Your activity can and is being monitored by hackers hired by the record and movie studios to catch you trading copyrighted works.
3). Many of the files have viruses embedded which will defeat hardware and software firewalls. A good, up to date antivirus program may detect and stop the infection in time if you have it set up properly.
4). Most of the movie files and many music files are now fakes posted by the recording and movie company hackers to choke the file sharing networks.
Really not worth messing with anymore.
PS WinMX sucks compared to Kazaa which is pretty disappointing anymore.