This just in – the Nokia Lumia 900 is expected to launch on AT&T on March 18 for $99 with the purchase of a two year contract.

The Boy Genius Report is reporting that they have a portion of AT&T’s roadmap for 2012. According to their story, the ‘roadmap’ was leaked to them from a “trusted source.” The report from BGR confirms a story from Paul Thurrott earlier this month on Windows Weekly. Thurrott is also reporting on his blog, Supersite for Windows, that there is an unconfirmed rumor that other carriers will be offering the Nokia Lumia 900 a Nokia-Lumia-900bit later on this year. While Microsoft, Nokia, and AT&T have all claimed that AT&T will have an exclusive on the new phone, Thurrott’s source says that it’s a “45-day exclusive hold on the Lumia 900,” not something that AT&T will have all to itself indefinitely.

So what’s so exciting about the Lumia 900? It’s the first Windows phone that will run on AT&T’s 4G LTE network. The fast smartphone has the largest display of any Nokia phone, 4.3 inches. It has a 1.4 GHz processor, 512MB RAM, and a whopping 16GB of internal storage. The camera is 8 megapixel with Carl Zeiss optics. The Nokia Lumia 900 won CNET’s Best of CES Smartphone Award at the 2012 Consumer Electronics Show (CES) earlier this month. Nokia considers the phone a game-changer in its US marketing strategy, where they have struggled to compete against Apple and Android smartphones.

There is one caveat to the expected launch date, BGR says the phone has not “received technical acceptance” yet, so the launch date might change based on that.