Something big is happening in the small world of portable gaming.

Much of the buzz comes from Sony’s unveiling at the recent Electronic Entertainment Expo of its PlayStation Portable, a portable device that promises not only enhanced game play but also the ability to play movies and download music. It has been likened to Apple’s iPod with a video screen.

The move is seen as a shot at Nintendo’s GameBoy system. But Nintendo has big plan of its own, with the next-generation Nintendo DS. Though lacking the multimedia functions of Sony’s PSP, the DS promises dual-screen action with wireless gaming.

Though both systems were available for previews at the expo in May, some uncertainty about their readiness remains.

"Normally we’d be seeing more about (both systems) by now if they’re going to be out over the next few months," said Jeff Gerstmann, senior editor at online gaming resource GameSpot. "We should have heard more as far as availability and pricing. There are still a lot of variables at play."

The PSP will be available in black, with a 4.3-inch wide-screen TFT LCD that displays full color on a 480x272 pixel high-resolution screen. Dimensions are 6.7 inches high, 2.9 wide and less than an inch tick. It weighs about 9 ounces.

The PSP includes built-in stereo speakers, exterior headphone connector, brightness control and sound-mode selection. Keys and controls are the same as Sony’s Play Station and PlayStation 2 consoles.

The PSP also comes with USB 2.0 and WiFi connections for various home-network devices and wireless networks outside the home. The device will allow users to play games online or to connect multiple PSP’s to each other directly via the wireless network.

Sony says that about 100 game developers and publishers have expressed support for PSP.

"The key to Sony’s entry into portable gaming is that they see it as an opportunity to grow the market in terms of the gap of folks who may own a next-generation console like PlayStation 2 but who don’t own a GameBoy," said Michael Gartenberg, a senior analyst at Jupiter Research. "That said, it will probably come with a pretty high price point, or at least go beyond the traditional GameBoy type marketplace."

That’s a problem for many gamers.

"There is definitely a lot of excitement about PSP," Gerstmann said, "but no one is going to pay $500 for a portable game machine. The traditional market can’t afford that – especially when you’re paying $100 for the GameBoy Advance. The theory is that they’re going after the older market, but I don’t know if that market is necessarily interested in something like this."

Sony has promised to release the PSP in Japan by the end of the year, followed by a rollout in North America and Europe in early 2005.

Those who have seen PSP are mostly impressed by it. The sharpness of the picture and graphics get high marks, and the added multimedia applications are seen as an obvious bonus.

"Sony has been very successful in gaming on their own, with PlayStation and PlayStation 2 being the best-selling gaming devices of the past decade," Gerstman said. "The PSP, which allows you to play music and movies as well, could definitely shape up to be the next Walkman."

Nintendo’s DS (for "dual screen"), at about $150, could revolutionize game play, with each of its 3-inch screen reproducing 3-D views and allowing users to simultaneously experience a given game from two perspectives: in a racing game, for instance, drivers could see their own vehicle’s perspective on one screen and the overall track on the second, or in a role-playing game could view their character’s perspective on one screen and the overall environment on the second.

The lower DS screen also offers PDA-style capabilities, with players able to move characters, shift perspectives and navigate menus with a stylus or fingertip.

Nintendo says future developments could allow users to play games on one screen and text-message fellow DS users on the other, while a microphone port could allow users to tell their games what to do; the DS software could be used to identify anything from voice commands to handclaps.

The DS also employs two wireless modes: one for short-range gameplay and one using Wi-Fi for Internet gaming. It also has multiplayer support for up to 16 gamers.

Though Nintendo has yet to release detailed specs or pricing, the DS will be backward compatible with existing GameBoy Advance titles.

On the downside, those who demoed the DS at the electronics expo say its extra screen and wireless technology could be a drain on battery life (Nintendo claims 10 hours of play on a single charge), and that using the stylus can b e cumbersome.

"The potential is great," Gerstman said, "but the demos were a bit underwhelming. They had an air-hockey game that was like an early Pong game – you had to use this stylus to move the puck around. It’s really not the killer app that everyone is looking for."

The DS is expected to be on U.S. store shelves in time for Christmas.

Though Sony and Nintendo’s aim appear squarely at each other, Gartenberg said, "Both companies are going after a different user than the traditional gamer – an older gamer who already owns a newer console system. There are enough differences between them that they could both succeed."