ThinkGeek (http://www.ThinkGeek.com) has released the US$49.95 TK-421 iPhonecase for the iPhone 4 and iPhone 3GS with flip-out keyboard. It offers a physical QWERTY keyboard that rotates out when needed and hides behind the phone when no longer needed.
The TK-421’s case includes a built-in keyboard that connects to the device via Bluetooth. The keyboard powers up with its own built-in, rechargeable battery.
When not in use, a magnetic clasp keeps the keyboard in place. The keyboard works with all native iPhone apps that support keyboard input, like e-mail, notes and the Safari web browser.