Send sound output over internet in realtime

[Ouoertheo]

Is there anyway to stream audio over the internet in realtime? Preferably something compatible with jack. The point is to do realtime collaboration with a friend that's far away.

[SynthesizersFTW]

I've been thinking along the same lines myself lately. Any audio stream I/O can be piped over the net device...
What you're looking for is a two-way audio conference. I think this could be a good bet, try it out and report to us how it works:

http://www.mediaapplicationserver.net/downloads.html

...looks like you'll need both the mas core and mas-control-apps.

I'd try it out myself but it is 3am here.
Good luck!