Philip K. Dick is, bar none, my favorite writer. His books and novellas have been made into movies before, some brilliant (Blade Runner), some flawed but worthy (Minority Reportand Total Recall), some hideously unwatchable (Paycheck).
In Dick’s dark oeuvre, it’s hard to imagine a book that’s more paranoid and inaccessible than A Scanner Darkly. So I’ve been awaiting its movie adaptation with some dread.
Based on this trailer, all I can say is, whoa. This looks good. Really good.
(Thanks to Prof. Froomkin for the pointer.)
Ed Bott 
Looks great! I’m always glad to see any of his stories make it to the screen. I had a screenwriting professor who knew him and said he was quite genious and quite mad.