Gobby

Gobby is a free collaborative editor supporting multiple documents in one session and a multi-user chat. It uses GTK+ 2.6 as its windowing toolkit and thus integrates nicely into the GNOME desktop environment. Gobby for Linux features realtime Collaboration through encrypted channels, each user has its own changeable color to be identified by others, IRC-like chat for communicating with your partners while coding, syntax highlighting for most programming languages, session password protection, multiple documents in one session, drag'n'drop of documents into Gobby, document synchronization on request, zeroconf and unicode support.