We have been developing this open source library for the past couple of years for Canvas 3D (the precursor to WebGL, works in Firefox 3.5.x only, requires Canvas 3D addon available from http://addons.mozilla.org). We are currently in the middle of making the port to WebGL and testing across multiple browsers.

You can find out more about c3dl from:
http://www.c3dl.org

Our official releases are currently Canvas 3D only but as we make our port, we are putting things on our svn server:
svn://cdot.senecac.on.ca/canvas3d