I've always been a great believer in there being no such thing as a free lunch when it comes to using the internet and this is particularly true in relation to music acquired on-line. Yes you can get music for "free" on the internet provided you are happy infringing copyright and running the risk of prosecution if you are found to be in breach of copyright laws. You should also be comfortable with the possibility of picking up more than you bargained for (spyware or viruses) when using a program like Kazaa, Bearshare, Limewire, eDonkey, Gnutella, AudioGalaxy, Grokster, Morpheus or any of the other P2P (peer-to-peer) file sharing programs that are available. Putting aside the copyright infringement aspect of P2P activity for now, peer-to-peer means that there is no central server involved in the transfer of the music file. It is transferred to your machine from the machines of potentially thousands of other individuals who may not all play the game as fairly as you. Is that file called KaiserChiefs.mp3 really the Kaiser Chiefs' latest album or is it possibly a carrier for a virus payload that may do serious damage to your PC.?
You see, when it comes to P2P filesharing the basic problem is that there is no quality control performed on the files that are transferred. Many of the songs downloaded are of poor quality, ripped at too low a bitrate, or are incomplete - starting or stopping abruptly. This is inconvenient, but hardly critical. What is critical, to my mind, is the fact that many P2P programs introduce spyware to your PC (have you ever read the EULA - end user license agreement - before installing a P2P program? Take a closer look next time or check out section 9 of the Kazaa EULA here to see all the "extras" that get installed that you probably know nothing about). Also of concern is the fact that there is no "adult" checking what actually is in all those files going between machines.
So what to do. Well, there are plenty of legal, quality-controlled, server-based commercial providers of on-line music out there and you can find an excellent comparison of the key players here. My favourite for obvious reasons (cost and absence of DRM) is www.allofmp3.com and you can read more about this site and how it manages to tip-toe through the legal copyright minefield at this link.
Whatever commercial site you choose to buy your music from now is the time to ditch the P2P software on your PC and go commercial. If I can't convince you to do it now, perhaps you'll be persuaded when you have to pay €€€ for a system rebuild. You'll learn that "free" is a relative term.