There are two websites that often serve as the folks lighting the lanterns in Boston, if you will. These people see the British (the deals), and they put out the signal. Your TechCrunches, Mashables, IGNs, etc. — they are the Paul Reveres of Black Friday.
Remember that. Someone knew before Paul Revere.
There’s an entire Black Friday section here, complete with scans of every retail flyer you could possibly care about. For general tech products, it’s the only site you need.
If you want info on deals for games, specifically, the forums at Cheap Ass Gamer are the place to go. Deals and discounts often show up here before I see them anywhere else, and they routinely have flyers for game shops and retailers 1 to 2 weeks in advance.