The latest updates to LR and ACR are available.  In Lightroom, go to Help>Check for Updates.  Download the file, then double-click on it to launch the installation wizard.  In Bridge or Photoshop, go to Help>Updates, and the update will be downloaded and automatically installed.  If you use both Lightroom and Photoshop, be sure to update both.

From product manager Tom Hogarty:

These updates include camera support for the following models:
Canon EOS 1D Mark IV
Canon EOS 7D
Canon PowerShot G11
Canon PowerShot S90
Leaf Aptus-II 5
Mamiya DM22
Mamiya DM28
Mamiya DM33
Mamiya DM56
Mamiya M18
Mamiya M22
Mamiya M31
Nikon D3s
Olympus E-P2
Panasonic DMC-FZ38
Pentax K-x
Sigma DP1s
Sony A500
Sony A550
Sony A850

Release Notes:
Camera Raw 5.6 and Lightroom 2.6 provide a fix for an issue affecting PowerPC customers using the final Lightroom 2.5, Camera Raw 5.5 and DNG Converter 5.5 updates on the Mac. The issue, introduced in the demosaic change to address sensors with unequal green response, has the potential to create artifacts in highlight areas when processing raw files from Sony, Olympus, Panasonic and various medium format digital camera backs.
The Lightroom 3 beta has not been updated with this new camera support. If you’re working with one of these newer cameras and the Lightroom 3 beta, please use the DNG Converter 5.6 to convert proprietary formats to DNG files that can be used in the Lightroom 3 beta.
This release includes improved camera profiles for the Leica M9 and Ricoh GXR.