If you're an OS X developer, go get Hydra NOW.

Hydra is a network-enabled collaborative editor. Open a source code file, click "Share". Then your fellow LAN (Rendezvous) or internet-based developers can conenct to our machine and you can work on the file in tandem. It's perfect for small-team/XP development. Wow. Wow.

Support for C, C++, CSS, HTML, Java, Javascript, LaTeX, Objective-C, Pascal, Perl, PHP, Python, Ruby, SQL, XML included.

Immediate feature-requests:

• a dock-icon marker showing that there are new changes in one or more of your documents
• an "Invite" command

This is seriously cool… stuff.