That tumorous little keyboard thingy for the 360 pad's got a name. And a price. And a release date! Now dubbed the Xbox 360 Messenger Kit (just rolls of the tongue), it'll set you back $30 and should, God willing, be sitting on a retail shelf sometime in September. At least in the US. We'll get you European and Australiasian info later today as MS folks wipe the gunk from their eyes and shamble off to work.
Xbox 360 Messenger Kit [Xbox.com, thanks Slurms!]