The OpenGL 3.0 specification was published by the Khronos Group in July of 2008, but up to this point there isn't any open-source Linux graphics driver with full support for OpenGL 3.0. This is while the latest ratified OpenGL specification is already up to OpenGL 4.2.
Ian Romanick along with Kenneth Graunke of Intel's Open-Source Technology Center (OSTC) gave a talk today at XDC2011 about the long road to OpenGL 3.0. In terms of when OpenGL 3.0 support will be official, "We think it will happen this year!"
There's still a fair amount of work left before the Mesa stack is in complian with OpenGL 3.0, but they have a number of developers working on the support at Intel. There's also many community Mesa developers and other companies with great interest in seeing GL3 compliance. On the FreeDesktop.org Wiki they have a work queue page detailing the OpenGL 3.0 work and the estimated time for completion.
If OpenGL 3.0 support is done in fact by year's end, Mesa 7.12 will be re-branded as Mesa 8.0. Mesa 8.0 is the release to tag once there is OpenGL 3.0 compliance. When talking with Ian afterwards, if OpenGL 3.0 support is not done by year's end but is quite close, the Mesa 7.12 release might be delayed to accomodate the OpenGL 3.0 support. (Right now Mesa 7.12 is expected for release in January.) Otherwise it would be another six months of waiting before seeing GL3.
Intel hasn't yet laid any plans for OpenGL 3.1 support (or OpenGL 3.2, 3.3, 4.0, or 4.1), but that will all be figured out once proper OpenGL 3.0 support is finally in place. "OpenGL 4 goes out quite a way," said Ian Romanick. It doesn't appear they have many tricks in their bag since then.
This is good news not only for the Intel Linux driver but the Nouveau and Radeon open-source drivers on Gallium3D can also tap this support from core Mesa. The proprietary NVIDIA and ATI/AMD Linux graphics drivers have meanwhile supported the OpenGL 3.0 specification going back to its debut in 2008.
Mesa 8.0 will be one hell of a release if it makes it out in January with OpenGL 3.0, better Intel Ivy Bridge support, and S3 Texture Compression (S3TC) support enabled by default.
The XDC2011 Chicago conference was organized by myself and is taking place from 12 September to 14 September in Chicago, Illinois.