Always good to see discussion of GRRM around the interwebs :)
Yup, Bantam and Amazon seem to be getting into some pretty heavy speculating, constantly sticking up speculative release dates and grinning in hope that GRRM will be able to manage it. But as others have said, we will hear on his blog and on his news page when he finishes and not before and not elsewhere. To get this book out in 2009 he needs to finish by the end of June/start of July at the latest, so we should know in the next two months if he's managed it. It's going to be close, and we may end up with the Clash of Kings situation again, where the UK version comes out at the end of the year and the US one comes out at the start of the next.
Hedge Knight fans will be pleased to hear the third Dunk 'n' Egg novella, THE MYSTERY KNIGHT, is finished and will appear in a new anthology called WARRIORS, which will be released in March 2010 and feature new stories from Robin Hobb, Tad Williams and a few others as well as GRRM.
As for the HBO TV series, there's been a lot of news on this recently. The pilot starts filming in October at the Paint Hall Studios in Belfast, Northern Ireland. HBO are casting right now and announcements are expected on that side of things in a few weeks. The pilot script leaked out and was praised by all, since it is very close to the first 80-90 pages of the novel. There's some new scenes (all approved by GRRM, who is serving as producer), mostly giving a better new entrance for Tyrion (he is at Chataya's in King's Landing indulging in his favourite pasttime when Jaime bursts in to tell him they're going to Winterfell). Daenerys' storyline is included (some thought it would be cut). The first line is, "We should start back," and the last line is, "The things I do for love." HBO are probably thinking that there is no way anyone will not tune in for episode two after seeing that :)
The schedule for the TV series is that the pilot will be filmed in October-November and HBO will make a decision on whether to go to series or not in early 2010. Assuming they give the go-ahead, filming will recommence in spring/summer 2010. The earliest the show will air is likely to be early 2011, although late 2010 is not entirely impossible. It depends on how soon they can recommence shooting once the commission is going.