Apple has just released an update for the 2nd generation Apple TV, version 4.4.4 (9A406a). As of now we know the update brings bug fixes, but we’re checking for more. Hit up your Apple TV to download the new firmware or hit up the direct link.
Update: Apple has also released a small update to the iPhone 4S, bringing it to version iOS 5.0.1 (9A406). Hit up the the direct link.
Update X2: Apple has dropped a note saying that this update fixes SIM card issues on the iPhone 4S.