I use direct connect and/or direct connect++
http://dcplusplus.sourceforge.net/
this thing is ultimate for just about anything you could want. its a hub-based system with different hubs pertaining to different things like software, music, games, etc. and all the different kinds. you want underground music? you WILL find it here. anything from norwegian black metal to amish music lol. the only thing about it is, different hubs have different rules, such as a minimum share size for each user to enter the hub, and shit like nazi and child porn related stuff will always result in a perma-banz0r (so all you fuckin freaks can look elsewhere lol). and would you believe there are PETAbytes worth of files on this network???
I used to live by kazaalite, but since it was getting too much spotlight from RIAA and i've heard people mention better p2p programs, i gave it a shot, and i HIGHLY recommend it to ANYBODY. you'll be hard-pressed to get another one of those "scrambled" mp3s and other bum files (although if you like underground shit thats not usually a problem anyways).