Adobe just released Adobe Camera RAW (ACR) 5.7 for Photoshop CS4 and 2.7 for Lightroom 2.
The release includes support for several new camera models and an upgraded RAW processing engine (Camera Raw 5.7 includes an updated demosaic algorithm designed to provide compatibility with settings applied in Lightroom 3.)
The read me files for Lightroom are here
The read me files for Photoshop CS4 are here
Download Photoshop 5.7 for Windows here
Download Photoshop 5.7 for Mac here
Download Lightroom 2.7 for Windows here
Download Lightroom 2.7 for Mac here
I haven't had a chance to look at the new RAW processing engine yet, so stay tuned.