NEW YORK (CNN/Money) - Faced with declining sales of its strongest product, Nintendo unveiled an enhanced GameBoy Advance Tuesday, which it hopes will reinvigorate interest in the portable gaming market.

The GameBoy Advance SP will feature an internal light, allowing users to play games in dimly lit or dark areas. It's a feature GameBoy Advance owners have clamored for -- and the company has been criticized for ignoring -- since the machine's launch in June 2001. The device will also have a rechargeable battery.

The machine will go on sale in the U.S. on March 23, with a retail price of $99.

Nintendo's GameBoy Advance SP

The new machine is much more compact than the existing GameBoy, measuring just 3.5 x 3.5 inches. Additionally, it uses a flip-top design (similar to many cel phones) that is only 1 inch thick when shut. Nintendo said the lithium-ion powered battery will last for up to 10 hours when the system's light feature is used - and up to 18 hours when the light is turned off. The company estimates the battery life to be approximately three years

The current GameBoy Advance (which sells for $70) will continue to be sold at its current price. Nintendo said it had no plans to discontinue the GBA, but Mike Wallace of UBS Warburg said he expects the company will eventually begin to phase those out. All existing GameBoy Advance and titles for other GameBoy systems will play on this new machine.

The GBA has been a hot seller for Nintendo, with more than 9 million systems sold in the U.S. In the past year, those U.S. sales have stagnated significantly, dropping roughly 20 percent, which is cause for concern at Nintendo. Its other console system, the GameCube, has not performed as well as expected against Sony's PlayStation 2 and Microsoft's Xbox.

Until today's announcement, the Afterburner was the only way to get a backlight for your GBA.

The decision to leave a backlight out of the original GameBoy Advance was an intentional one by Nintendo, which said at the time that such an enhancement would drive the machine's cost above $100 and would significantly drain battery life. Gamers complained loudly, however. Many had hoped the company would hear their complaints about the lack of a backlighting feature on the GameBoy Color (the machine's previous generation).

Third-party hardware companies quickly offered "worm lights" and other lighting alternatives that were close cousins to the Itty Bitty Book Light, but the end result was a glare on the screen that made it even more difficult to see what was happening in the game.

In mid-2002, technically adept GameBoy Advance owners were offered a solution with the Afterburner, which let you install your own internal lighting system to the GameBoy. Though installing the device voided the GBA warranty and required technical skills beyond the ability of most gamers, it has been a big hit, according to TritonLabs, which makes the Afterburner.

"Business has not slowed down one iota," TritonLabs CEO Adam Curtis said in December. "In fact, we have been having great trouble keeping up this holiday season, and signs are pointing to next year being even bigger than this year."

The GameBoy Advance SP could have ripple effects in the software industry. Several game publishers, including THQ (THQI: Research, Estimates) and Capcom, release dozens of GameBoy titles per year. A surge of demand for the hardware could spur software sales – and have a modest effect on publishers' bottom lines.

At the very least, it will earn Nintendo some goodwill with gamers – not to mention parents of small children on the road at night.  

Morris is Director of Content Development for CNN/Money. Click here to send him an e-mail.