The new 32nm Sandybridge processors will continue to be marketed under the Core i3 / i5 / i7 branding for both mobile and desktop processors, but thanks to a new code commit to the Intel X.Org driver we have a look at their different variants. On the Intel Sandybridge desktop side there is the GT1, GT2, and GT2+ graphics processors. On the mobile side there is also GT1, GT2, and GT2+ models with different PCI IDs from the desktop varaitants. Lastly, for Sandybridge-derived server processors there is just a single "GT" graphics processor. This is their current Sandybridge portfolio.
So while there has been initial Linux GPU support for the Sandybridge graphics going back to the Linux 2.6.34 kernel, not all of these models are supported. The only PCI IDs in the DRM and DDX components up to this point have been for the GT1 on the desktop and mobile side. On the mobile side though there was previously a Sandybridge mobile "D0" model, which now it turns out to be that's the GT2+ model. There was no support for Sandybridge server graphics in the open-source stack up to this point. What this means is that there won't even be first-cut open-source support for Sandybridge GT2/GT2+, mobile GT2, or server GT support in Ubuntu 10.10 and other Linux distributions that have already pulled in their DDX and DRM code in for their Q4'2010 releases due to these missing IDs. So unless rolling your own kernel and X.Org driver with this hardware, you'll have to wait for Ubuntu 11.04 and other H1'2011 distributions before seeing widespread Sandybridge GPU support on Linux. At least by then the open-source Intel support for their sixth-generation graphics processor should be more mature for all hardware variants.
The IDs for the Sandybridge hardware can be found in this Git commit. There's also been some other Sandybridge-related work recently too.