Currently the plan is to have the animated story-within-the story "Tales of the Black Freighter" released on DVD five days after Watchmen opens in the theater on March 6, 2009. Gerard Butler will provide the voice for the main character.
That DVD is expected to include a backstory segment on the Watchmen characters entitled "Under the Hood" (Watchmen readers will recognize that phrase.)
Then, the Watchmen DVD will be released in July 2009 (I would think that would be in conjunction with the annual San Diego ComicCon).
Then, holiday season 2009 an Ultra DVD release with the Watchmen and "Tales of the Black Freighter" edited together as one movie--just as it is in the Watchmen graphic novel.
Rope of Silicon article.
And, don't forget you can read more about "Watchmen", and Patrick Wilson's other projects at Patrick Wilson Fans--the NEW UnOfficial Site. News, photos, links, and a great messageboard!