Media Machines have just released to Flux Source code to open source!
http://www.marketwire.com/mw/release_html_b1?release_id=142369
This is the X3D plugin which comes with VizX3D for those who don't know. It displays much of the vrml content out there also, but there are some things it doesn't like, no multiuser.
It also works as firefox plugin, something contact doesn't do at the moment.