Looks like some retailers are starting to get supplies of Xbox 360 gear and games. Amazon has quite a selection of games and peripherals for Xbox 360. Here is a list of the games and peripherals available at press time.

Games:
Call of Duty 2
Madden NFL 2006
Need for Speed: Most Wanted
Project Gotham Racing 3
Perfect Dark Zero Limited Collector's Edition
Perfect Dark Zero
GUN
Condemned: Criminal Origins
Tiger Woods PGA Tour 2006
NBA Live 2006
Kameo: Elements of Power
FIFA 2006
Tony Hawk's American Wasteland
NHL 2K6
NBA 2K6
Amped 3
The Incredibles 2: Rise of the Underminer

Peripherals:
Face Plate - Woody
DC: Justice League Controller

Link for more information