It looks like Snow Leopard will eventually support OpenGL 3.0, but Apple has a long way to go before support is complete.
For some time now, Mac OS X has been stuck at OpenGL 2.1, but the latest developer beta contains a number of 3.0 specifications. Ars Technica predicts, “Later revisions of Snow Leopard may include full support for the updated standards, but chances are good that 10.7 will definitely include full support.”