Mobile phone joint venture Sony Ericsson will release the PlayStation-certified, Android-based Xperia Play phone next month, the company confirmed at a Sunday media briefing.Executives with Sony Ericsson said the device - whose full specs were also detailed via press release - will start shipping worldwide in March this year, with U.S. customers among the first to be able to buy the phones.U.S. mobile operator Verizon will be the first carrier to have the phone in "early spring," making the device available to the carrier's 94 million customers.Sony Ericsson marketing head Steve Walker said his company is currently working with other mobile carriers, which he expects to also soon reveal Xperia plans.The mobile phone company said it will have 20 game publishing partners at launch, including Electronic Arts, Namco Bandai, Digital Chocolate, Gameloft and Glu Mobile.Games mentioned at the press briefing included Trendy's, EA'sandfranchises, EA and Pixelbite'sand Ubisoft'sSony Ericsson said Xperia Play has 50 titles confirmed to be ready for launch, and that number is growing. There will also be classic PS One titles coming to the device.Also partnering with Sony Ericsson on the Xperia Play is major game engine provider Unity Technologies, which has 350,000 registered users worldwide who will more easily be able to bring their Unity-based games to the Xperia Play. It's the first time that Unity has partnered with a platform manufacturer like Sony Ericsson.Sony Ericsson confirmed that the Xperia Play, which has a slide-out gamepad that features a PlayStation-style D-pad, thumb sensors and X, O, square and triangle action buttons, will be based on the Android Gingerbread OS.The Xperia Play will also be the first PlayStation-certified phone. Sony said last month that it will work with hardware manufacturers to release these licensed phones. Sony's recently-announced PlayStation Suite initiative will bring other Android-based games to mobiles, helping address the market for smaller, less expensive mobile games.The Xperia Play is just part of Sony's portable gaming plans. The company late last month also revealed the high-end dedicated portable gaming device, the codenamed Next Generation Portable.Sony revealed three other less game-centric Xperia phones during Sunday's media briefing: the Xperia Arc, Xperia Pro and Xperia Neo. Prototypes of the Xperia Play began surfacing last year, and a Super Bowl commercial early this month confirmed the existence of the long-rumored device.