www.digitalmusician.net
it’s a PLUGIN that allows you to link to another user via broadband and record them, or vice versa. Pretty Freakin’ cool. It doesn’t quite do real time jamming as latency is a factor, but you can hear each other fine. 
put the plugin in your master effects channel for your partner to hear everything.
example,
set up track one as a mic for talkback
set up track two as a guitar input
set up master channel with the plugin
then you can talk and play guitar and your “partner” can hear it