I probably should have been more specific; I'm interested in remote pair programming. As it stands now, we end up using Mac's built in screen sharing app but this has a less-than-stellar responsiveness that's typically needed when two people are going back and forth making changes to the code..

I've written up my thoughts on what is needed ( https://gist.github.com/1999816 ). TL;DR - a lightweight protocol to share buffer updates, tab changes, opening files, etc.