The DLC will be available on Steam today in English, French, Italian, German, and Spanish, for $19.99, Bethesda says. And wouldn't you know it – Skyrim itself is on sale today, for $29.99! It's also available as part of a massive "QuakeCon bundle."
The PS3 version, however, is not out today. "We are not satisfied yet with Dawnguard's performance on the PS3," a representative wrote in an update on the Bethesda blog today. The rep did not offer an estimated time frame on the release, expressing the company's disappointment at not being able to provide all Skyrim content to all platforms at the same time.