With most of the action now happening within the Linux kernel, landing Ivy Bridge support in the DDX driver is relatively trivial. In this Git commit that's just 32 lines long it provides initial support for Ivy Bridge. However, this just gets the display lit up and 2D blit acceleration. X Render acceleration is not up yet for Ivy Bridge.
Fortunately, the xf86-video-intel driver release schedule is under Intel's control and is something they push quarterly. This should give them time for the xf86-video-intel 2.16 and 2.17 releases to iron out the DDX support and for the driver to land in mainstream distributions before the hardware is actually shipping. On the kernel side the support is in Linux 2.6.40 and will likely be further refined in the Linux 2.6.41 kernel, which is likely what will be found in Fedora 16, Ubuntu 11.10, etc.
Intel hasn't yet landed any OpenGL acceleration support for Ivy Bridge, but you can expect them to update their classic Mesa driver in due time (don't expect them to move over to a Gallium3D-based architecture in the near future).