The DEMO launch you can hold in your hand is the Zink cellphone photo printer. It uses dye embedded paper inside of a pocket-sized printer to do wallet sized prints. The competition? There isn't any.
The printer transfers by Bluetooth, images of up to (maybe beyond, 3MP), downscales them internally, and pushes out prints via a simple roller. The 2x3-inch, 300 DPI shots look fantastic.
Pricing on paper is approximately 20 cents on a on a 2x3. The printer's battery lasts 20 prints per charge, and juices by USB. The internal paper tray will hold 10. Prints take for about a minute to finish from send (video after the jump). Prints are water resistant and durable enough for wallet duty, which is appropriate for a print of this size. Not bad for $99 bucks. It'll be out later this year, and I predict it'll sell like hot cakes.