You may remember the Fling iPad controller revealed at CES 2011 earlier this year. Well the product is here, and not only this but it's available at Apple Stores everywhere. Ten One Design also sells the Fling analog joystick for iPad on their website for $19.95. Purchase two and you get a $10 discount, bringing the price for dual-handed iPad control to $29.95.
The concept is really simple and has already received rave reviews including Macworld's Best of Show for 2011. The Fling is clear plastic, so it doesn't interrupt the visuals of the game you're playing on the iPad screen. The joystick uses suction cups to attach to the glass above in-game touch control areas, converting them into a real, tactile controller.