A $99 Lumia 900: Just what Microsoft and Nokia need

Updated. After much anticipation, AT&T (s t) officially announced launch details for the Nokia(s nok) Lumia 900, the first LTE Windows Phone(s msft) handset for the U.S. On April 8, the Lumia 900 will be available for $99 with a two-year plan commitment, making it one of the least expensive LTE phone debuts to date. Such pricing is likely backed by a higher level of subsidies from Microsoft, Nokia, or both, in order to restore both brands to prominence.

The new Lumia model runs on Microsoft’s Windows Phone 7.5 operating system and uses a 4.3-inch display with Nokia’s ClearBlack AMOLED screen technology. A wide aperture (f/2.2) and angle lens (28 mm) with 8 megapixel camera and dual LED flash adorns the back of the device while a 1 megapixel front camera is available for video chat apps. Note that Microsoft purchased Skype last year and is working to integrate the service into Windows Phone.

Neither AT&T nor Nokia appear focused on marketing the specifications for the Lumia 900, but specs matter less when it comes to Windows Phone. I’ve run it on a two-year old smartphone with a last-generation processor and it’s at least as fast for most tasks than any current phone on the market. The Lumia 900 uses a single-core 1.4 GHz processor, for those that wonder, but like Apple’s iOS(s aapl), Windows Phone is optimized for slower chips; that helps with performance and battery life.

Having used — and been impressed with — a Nokia 800, which is similar in design, I suspect most will find the hardware to their liking. And it’s paired with Windows Phone 7.5, which is a solid improvement over Microsoft’s initial smartphone platform, launched in 2010. Windows Phone 7.5 also just topped 70,000 apps in its Marketplace.

Combine that with LTE service in a growing number of AT&T markets, along with a low $99 up-front investment and the Lumia 900 could mark the biggest step yet for the mobile comebacks of two one-time leaders: Microsoft and Nokia. I have a review unit already lined up, so I’ll have a chance to see if I’m overly excited by the Lumia 900 package or if I’m right about that comeback.

Update: Prior to publishing this post, I asked AT&T what the no-contract price for a Lumia 900 will be. After publication, AT&T responded: $449.99, which is generally far less expensive than prior unsubsidized Nokia phones in the U.S.