WebGL spec is final
Khronos released version 1.0 of the WebGL specification a few days ago at Game Developers Conference in San Francisco.
Khronos also mentioned another thing in their press release, namely the formation of the WebCL working group which will work on a similar spec for bindings to OpenCL which could be very interesting.
Go ahead and try some of the demos, but for full conformance you need a modern browser such as Chrome 9+, Firefox 4+ or Safari OSX 10.6+. They will probably work in Opera 11 as well.