Michael Lucas-Smith talks about wanting to be able to share his code browser over IRC. This is something I've talked about with my remote clients as well - one of them took a few minutes to implement a tiny proof of concept with Jabber, which would send a message each time a method was edited, but we never dealt with receiving. It's an idea I'd like to play with further.
A related idea that came up on the Squeak list was having a channel for each package that you would get automatically logged into whenever you were browsing or modifying that package's code. That way you'd be instantly connected to any other Squeakers that happened to be working with the same code that you were. I guess things would get really interesting if you could decide to then sync your browser (but for only that package?) with any of them... ad-hoc adaptive pairing.
Obligatory plug: in how many other language environments would you even consider trying something like this, as an afternoon hack?