Lymewire

They are both pretty old and very hackable.

Try Kazaalite Revolution or Resurrection (1st one is less problematic), it is an ad and spyware free version of the Kazaa desktop. It includes supernode retention (Kazupernodes) , an IP blocker, an IP Hosts manager that gets rid of ads and crap in IE, KNAT for IP emulation when on a network or behind a firewall. and abucnh of other goodies, such as an MP3 validator to stop you downloading dead or crappy MP3'2, AVI preview for scanign AVI downloads befor ethey are complete etc.

http://www.softpile.com/Internet/Search_Tools/Review_37803_index.html

It uses the sam eFasttrack client as others so the network is at about 2.5 million users most of the time.

NOTE: P2P sharing is illegal in the US when it comes to copyright protected materials. Nothing is really being done about it but it is still not legal in the US. You will find the UK's Limewire and several variations have been shut down for the open source offerings, thus you copy of Lymwire.

Try the link above, it is better , less hackable and more accurate. Make sure you study and understand the tools, they are what make it work better and retain your anonymity somewhat.