Order of the Phoenix is slated for release on Fri the 13th next July. I have mixed feelings about this one.  Mrs. Weasley is back, but still no Dobby.  And it looks like they got MOST of the casting right, but I always envisioned Bellatrix LeStrange as a bigger woman.  Not fat or chubby, but tall & solid, like she could bench-press a bulldozer.  Helena Bonham Carter is a hell of an actress & I'm sure she can pull it off, she just doesn't fit the image I had in my head.    Same goes for Dolores Umbridge - she needs to have no neck whatsoever & add 200 lbs, but most important, I wanna see that gaudy ribbon perched on her hair.
Pictures...
http://www.harrypotterfanzone.com/gallery/index.php?cat=46
and details...
http://www.comingsoon.net/films.php?id=4661

Absolutely no details but the release date for Half-Blood Prince: November 2008. 
http://www.comingsoon.net/films.php?id=11750

The seventh book is named, but she's not telling yet.  Fans are hoping for July 7th release next year (7/7/07), but WB & Scholastic don't want the 5th movie & the last book to compete for attention.  Then there's the fact that Rowling may need more time to finish.  *bouncing on the edge of my seat!!* 
Details & theories - plenty from Rowling herself...
http://www.veritaserum.com/books/book7/

I just re-read HBP - the ending didn't hit me near as hard as the first couple times I read it, I wasn't crying at the end this time.  Reading it now, I find myself wondering which bits they'll cut for the movie.  I am glad I saw *gag* GoF, even though they cut more from that than any of the previous movies, 'cause I have a better idea of what the kids look like a little more grown-up.  Better pic in my head, see? 

Well I've rambled on enough - somebody else gush over Harry!