NVIDIA has yet to officially deliver a new Linux driver to support the GeForce 9 Mobile parts; however, the latest release should work. The release we're talking about is 173.14.05, which had arrived less than two weeks ago.
For those interested in open-source support for these newest mobile GPUs, the story is a bit different. The Nouveau developers are still hard at work reverse-engineering the GeForce 8/9 series and writing the resulting 2D/3D driver. It will still be a ways out before the GeForce 9 Mobile support through Nouveau has been stabilized.
If you're alright with just 2D support and using an obfuscated driver, the "nv" driver has picked up support for these new products on Friday. A patch now in the xf86-video-nv git tree for several new mobile ASICs and removes support for the GeForce 9600 GS. The mobile parts that are now listed in this open-source driver include the GeForce 9200M GS, 9300M G, 9300M GS, 9500M G, 9600M GS, 9600M GT, 9650M GS,