Arcade fans can rejoice now that the iCADE, which started out as one of ThinkGeek’s annual April Fools’ Day joke products is now an order-able reality. In case you’ve been living under a rock, the iCADE is a retro-style gaming cabinet for the iPad and iPad 2. It has been specifically designed to safely hold your beloved tablet and transform it into a true desktop-sized classic arcade gaming cabinet complete with joystick and buttons.

“We partnered with ION Audio to make our vision of the iCADE a reality,” says Ty Liotta, head of ThinkGeek’s GeekLabs. “After it was announced as an April Fool’s Day joke back in 2010, thousands of our customers wanted it and we’re excited to make it a reality through this partnership.”

The iCADE is powered by two AA batteries and connects to your iPad via Bluetooth. Currently users can play 100 classic Atari games (including Pong, Asteroids, Centipede and more) on the iCADE by purchasing the Atari’s Greatest Hits app and associated DLC. now for download from the Apple App Store℠. In preparation for this release, Atari released 100 of its Classic games for use with the iCADE.

Details of the the SDK were also revealed and it sounds like it will be very easy (and free) for developers to add iCADE support to their own games. Many developers including Retro Dreamer’s Gavin Bowman have already stated that they will be adding support to their games (where appropriate) as well. I highly recommend you check out the great interview that they guys over at 148Apps conducted with Fred Galpern of Ion Audio regarding the new SDK.

The iCADE is available now in limited quantities for $99.99 directly from ThinkGeek.com.