Go to RobotStore.com or ParallaxInc.com in order to buy the stamp2 chips and a carrier board.
Robot Store Stamp Stuff
ParallaxInc Stamp2 Carrier Boards
The carrier board is great because it can use a 9V battery to power the Stamp2. All you need is a 9 pin cable and PC & you're coding to your heart's delight.
Hope this helps.
Joe J.