I have used psi-jingle (
http://mylinuxsaga.blogspot.com/2006/02/getting-gtalk-working-on-linux.html)
and it worked fine..got bored of having an imporper sound daemon which dint
let me talk if xmms/mplayer was playing (which is pretty much all the time
:) )..and it wasnt too stable either..you can give it a try if you want..
cheers,
Ganesh