The Elder Scrolls V: Skyrim - Dawnguard DLC Released on PC

After a full week of near silence, Bethesda Softworks has announced that The Elder Scrolls V: Skyrim's first DLC Dawnguard is now available on Steam. It won't be unlocked for every region yet, though it will most likely be available tomorrow worldwide.  Meanwhile, word on the PS3 port is that Bethesda is not yet satisfied with its performance:
We are not satisfied yet with Dawnguard's performance on the PS3. We would like for everyone to have a chance to play Dawnguard, but we aren't going to release it for PS3 knowing that some people's experience in Skyrim will be worse. We do everything we can to have our content available to all; from our free updates, to user mods, to paid DLC. We're as disappointed as our fans when that isn't the case, but we'll continue to push for that reality.