SubEthaEdit (formerly Hydra) is a Mac OS X collaborative text editor with advanced developer support that allows several users to simultaneously work on text documents on a local network.
It is based on the multicasting "zero-configuration networking" library, Rendezvous, which is also used by Apple's iChat.
See also MoonEdit.
Suppose you used SubEthaEdit like InternetRelayChat (or more like <tt>talk</tt>). Then you would essentially have a real-time refactorable chat. -- SunirShah