According to /Film the new film will be the movie equivalent of what's known in the comic book community as a "retcon", or creating retroactive continuity. That basically means that this will be a reboot of the onscreen version of The Hulk, disregarding the events of the first film.
Unlike a lot of folks, I didn't hate Ang Lee's version of the big green guy. I thought that perhaps he went with an overly serious take on the character, but I can't blame him. Bruce Banner is really a tragic character at his core and movie versions of comic book characters tend to examine the humanity of the superhero and a more real-world light than the comics. I also didn't have any complaints about the CGI version of The Hulk for similar reasons.
Louis Leterrier (who helmed The Transporter) is directing the new version and he describes it this way:
"Frankenstein meets Jekyll and Hyde with a little bit of Edward Scissorhands."
Leterrier has actually done some films that I've really enjoyed. The Transporter was a lot of fun, although it falls under the category of a one-viewing-movie (not really a "repeater") and his sequel to that was ok as a popcorn flick. I thought that his film starring Jet Li (Unleashed) was great.
On the down side, the screenplay is being written by Zak Penn, who was co-writer on such non-stellar far as Elektra, Fantastic Four, and X-Men: The Last Stand. No warm fuzzies there.