Adobe has released Photoshop Lightroom 2.3 and Camera Raw 5.3 updates

Adobe:
→Photoshop Lightroom 2.3 for Mac
→Photoshop Lightroom 2.3 for Windows

→Camera Raw 5.3 for Mac
→Camera Raw 5.3 for Windows

Camera Raw 5.3 is available through the update mechanism in Photoshop CS4, or as a standalone updater.