Updates are now available to Lightroom 1.2, and Camera Raw 4.3. The updates provide raw file support for 14 additional camera models and camera backs within Lightroom and Camera Raw, including the Canon EOS 40D.
We don’t know yet if there have been any other features added, but as far as we can tell this is not a huge update like 1.1 turned out to be. We’ll play with it however and keep you posted. Of course you can find out for yourself! You should get the auto updater as soon as you start Lightroom, and be able to get your own update.