A news item on the OpenGL homepage announces that the OpenGL 2.1 specification has been released. (I’ve just downloaded it and will post my thoughts after I’ve had a good chance to go over it).
The news post also mentions that:
The OpenGL ARB is also developing an OpenGL 2.1 SDK complete with reference documentation, sample code, tutorials, tools and utilities for release in 2006.
Here are links to the Khronos/ARB press release and the specification download page.