Just an FYI, Limewire, Kazaa, emule, edonkey, imesh, etc, etc are all called "file sharing" because you "share" programs on your computer with other people and they "share" programs on their computer. This sharing allows a user to transfer files to and from other computers.
The issue is that it is illegal (according to copywrite laws and what have you) to download music, games, programs from others since you did not purchase it yourself. The RIAA (music) and MPAA (movies) associates have been filing lawsuits left and right against EVERYONE............
A "legitimate" (legal) service to download music (
www.iTunes.com,
www.mp3.com, etc) typically charges $1 or so per song. So if you aren't using a service that charges, PLEASE be careful.
Check this website out for indepth information about filesharing including what it is and how to do it -
http://www.slyck.com/