In April 2010, Editshare.com announced they were going to create an open source version of their Lightworks Video Editor - a professional level editor which has been used in the creation of movies such as The Truman Show and Shutter Island.
The project has now entered beta testing, although I believe it is currently exclusively available to those who registered (free), it may be a project some here wish to keep an eye on.
It is also currently only available for Windows, but Mac and Linux ports are planned for the coming year. Personally I find this very exciting as we may soon have a free, professional level video editor thereby removing one of the major financial barriers for aspiring vidders and vidders who want the chance to work with something more than a very basic video editor, without having to put up with ugly and counterintuitive interfaces, a lower level of technical ability and/or being tied to a single operating system.
Anyway, enough gushing - for those interested in what the project will offer, the following link provides a list of specs and features:
http://www.editshare.com/email/lightworks-nov10-online.html