The movie's been in the works in one form or another since the 1980s. Starlog quotes Robbie Stamp as saying it's basically been underway for the last 25 years, about since the book came out and started at #1 on the best seller list.

MJ Simpson, who did one of the biographies of Douglas (his one time publisher Nick Webb did another, and it's finally been released in the US, just for the movie, and Neil Gaiman did the first,back in 1987) has penned a scathing review of the movie. The recent BBC review, just after the London world premiere, was a mixed bag. Both are available online, one at news.bbc.co.uk (look under entertainment) the other is on planetmagrathea.com

There's also some interesting background material, written by Robbie (one of the producers) included in the new tie-in editions of the book (in mass and trade paperback). And the movie soundtrack was released to the iTunes Music Store 2 weeks before the CD is scheduled for release, which should be released on 4/26. The iTMS also has some exclusive tracks, all featuring Stephen Fry (the movie voice of the guide): The Marvin Mixes, which are rerecordings/remixes of Marvin and Reasons to be Miserable (two songs recorded by original Marvin voice Stephen Moore in 1981, and released as "Marvin the Paranoid Android"), and Guide Entries - I'm assuming Stephen Fry wrote these himself, but it's hard to say.

There is a movie poster available on Amazon, and there ARE supposed to be figures/toys, according to ToyFare magazine. Whether they'll be "mainstream" (I.e. available at every Target, WalMart, Toys R Us) or "collectibles" (i.e. check your comic book shop or similar store) I don't know yet, but I've been looking.

Despite the reviews mentioned earlier, I'm still hoping to find a midnight show, as I'd plan to attend with a bathrobe and towel. And after the movie's released, the final 8 radio episodes will be airing on BBC Radio 4 (and probably webcast again, as the Life the Universe and Everything series was last year). These will be a little more loosely based on books 4 and 5, the 3rd series followed the third book rather well (in the uncut CD version) - the new producer has stated how he'd like to give a more upbeat ending to the series than Mostly Harmless, which is something DNA talked about before he died in 2001.