The novel is set in 1960s Southern California (an area that PTA knows well) and features as its main character a frequently stoned private eye named Larry "Doc" Sportello. We know that "Doc" will be played by Joaquin Phoenix, but no other casting has been announced.
This, of course, will not be the place to follow regular news about the new movie. For that, you'll want to read Cigarettes & Red Vines and follow it on Facebook and Twitter.
You can also find a coven of PTA obsessives at the slightly obscure (and it likes it that way) movie message board xixax.com. (I used to post there regularly in the early 2000s but am now correctly labeled a "Sell Out" in my profile.)
I haven't read the novel yet. It's on my reading list for 2013, as I mentioned in December. Usually, it's fascinating to compare the script to the film when it comes to PTA's work. For example, if you're familiar with "Boogie Nights," check out this snippet from the script and think about all the ways in which it differs from the movie.
(Big points if you cite the differences in the comments section. I admit, you probably have to be a bit obsessive about the movie, like me, to see where it differed.)
In this case, though, the fun will come in seeing how PTA "breaks the back" of Pynchon's novel and comes up with an entertaining film.