Like usual, the Intel Linux graphics package isn't some new software component release, but rather it's just what Intel recommends their customers and Linux distributions use for appropriate versions of the upstream Linux components to deploy when running Intel integrated graphics.
The Intel 12.07 graphics package comes down to using the Linux 3.4.x kernel, Mesa 8.0.4, xf86-video-intel 2.20, libdrm 2.4.37, libva 1.0.15, and vaapi-driver-intel 1.0.17. They also recommend using X.Org Server 1.12.1 although the xorg-server isn't officially part of this "package" for Linux. Basically these are all the latest stable package versions available right now, although soon to be succeeded by Mesa 8.1, Linux 3.5/3.6, etc.
Compared to the previous Intel Linux graphics package, these newer components provide RC6 power-savings (and performance improvements) for Sandy Bridge and Ivy Bridge, support for Ivy Bridge GT2 server graphics, general performance improvements, and many bug-fixes. There's also experimental 2D acceleration support for SNA and GLAMOR to complement the stock UXA 2D acceleration mode.
More details on Intel's 12.07 Linux graphics driver package can be found at IntelLinuxGraphics.org.