WebGL support makes first appearance in latest Firefox 3.7 nightly builds
Progress is coming quickly, but there are still plenty of issues to address before WebGL support is ready for prime time. Vukićević cites security and portability issues with shaders, as well as the problem of what to do on platforms where OpenGL is not available. He also promises some simple demos that will arrive in the near future. If you've seen some already, we'd love to hear about them in the comments! Apart from the Webkit globes, cube, and teapot, that is.
The Minfield (currently Firefox 3.7) builds are available from the Mozilla FTP. To enable WebGL support, head to about:config and change the webgl.enabled_for_all_sites value from false to true (double-clicking the value will change it).