Divx4Linux is available at divx.com. There was a Kazaa client until Kazaa closed their protocol, but check out sourceforge.net for other options. One you should check out is XNap (
http://xnap.sourceforge.net). Just search Sourceforge for "Kazaa", "eDonkey", etc.
SpaceAce
P.S. ->
http://www.mplayerhq.hu