The Lumia 900 is off to a nice start -- at least on Amazon. Nokia\'s flagship smartphone sits atop Amazon\'s cellphone bestseller list. In fact, the black variant is the top seller, followed by the blue version. They were both outselling the Droid Razr Maxx by Motorola Mobility and the Samsung Galaxy Nexus. That\'s a solid early indicator for a phone with a lot riding on it. Microsoft is looking for the Lumia 900 to break Windows Phone into the mainstream, while Nokia sees its phone as a way to get into in the U.S. market. AT&T has promised a massive campaign for the phone. Amazon, of course, only makes up a small percentage of total sales -- AT&T still sells most of its phones directly to customers through its stores and Web site. And the Lumia 900 is a brand new phone, likely generating more attention than phones that have been out for a few months. Nokia kicked off its campaign with a concert on Friday featuring Nicki Minaj performing in Times Square, which was covered in blue Nokia ads promoting the Lumia 900. The Easter Sunday meant a quiet day for sales at AT&T stores, but the company said presale orders for the device had been strong. AT&T, Microsoft, and Nokia will likely take all the good news they can get.