On May 1st, Behtesda Softworks have announced Dawnguard, their first major expansion for Skyrim.
Dawnguard will be released in summer this year for X360. PC and PlayStation 3 users will have to wait one more month for it to be available for their platforms.
Bethesda have not talked about any specific content yet, which they will soon (not later than at E3) submit, though. On the other hand, there are already rumors about possible content circulating:
- "Snow Elves"
- Appearance of the Mythic Dawn
- A journey to Cyrodiil
There's an Add-On upcoming which will offer more than just some new quests and a few new items, like Knights of the Nine did. Todd Howard himself once announced, that future Skyrim expansions will contain really huge amounts of new stuff which will actually stand out from the rest. We'll look forward to it!