That Palm OS or Pocket PC device in your hand has the potential to become a Game Boy, Commodore 64, Apple II, Nintendo, or just about any other piece of vintage gaming hardware. It's all made possible through the magic of emulation, which is when the processor on one device is used to exactly mimic all of the hardware of another device so that software programmed for that other device can be run. If you load an Atari 2600 emulator on a Pocket PC, for example, Atari 2600 games that are launched are fooled into believing that an actual Atari 2600 is there. They don't even "see" the Pocket PC hardware. This is different from "porting," which is when a game for one system is modified and recompiled so that it recognizes and works with the hardware on another system.

	Take Ms. Pac-Man on the road.

The beauty of emulation is that once the hardware is properly emulated, there is no need to modify the software. Porting the entire Atari 2600 library so that the games work with Pocket PC hardware would require reprogramming each game. It's easier to create an emulator that works with the Pocket PC hardware and then force the unmodified game files to work with the emulation program. These game files are called ROMs, as they literally are memory dumps of the Read Only Memory chips that stored the original games. It's amazing to think of the tens of thousands of ROM files floating around the Internet, considering how difficult and tedious it is to extract the contents of a ROM chip from either a game cartridge or an arcade motherboard. The good news is that other people have done all the work for you, so all that's left is to download the emulator files and find some compatible ROMs to feed them.

Proper emulation requires far more processing power than most people realize. It's hard to imagine that the 206MHz processor in an iPAQ would break a sweat emulating a gaming console from the 1970s, but the procedure is harder than you'd expect. In fact, the steep hardware requirements have pretty much kept Palm OS devices out of the emulation scene, aside from a few mediocre Game Boy emulators.

	You can even configure keys.

The simplistic controls on a Palm OS or Pocket PC device make them unsuitable for playing complex games, but they are ideal for emulated games. Older consoles and arcade games generally let you move in four or eight directions and give you a single fire button, so they are great matches for current PDA hardware. Programs that emulate more-complex hardware like Nintendo Entertainment Systems, the Sega Genesis, or a Game Boy typically come with "virtual buttons" that appear onscreen, expanding control options at the expense of responsiveness. They also have the side effects of making you get fingerprints all over your display.

	An Atari 2600 emulator for Pocket PC

There are far too many emulators to discuss in detail here, and new ones appear constantly. We did test a few of the more popular emulators to see how today's handhelds handle the incredible stress that these programs put on a processor. The Multiple Arcade Machine Emulator (MAME) is perhaps the most successful emulator ever created for PCs, capable of re-creating literally thousands of old coin-operated classics from the last three decades. Originally designed for use with PCs, the emulator has since been ported to every system that can handle it, including the Pocket PC. The best of these ports is MameCE3, which supports tons of games and worked flawlessly on our iPAQ H3650. We had a blast reliving arcade-perfect re-creations of hits such as Ms. Pac-Man, Q*Bert, and Galaxian. For more information on MAME and all the other emulators available for PDAs, check out our links at the end of the article.

We need to point out that it is illegal to download and use ROMs for games that you don't actually own, and technically, it's illegal even if you do own the games. For that reason, we can't point you to any sites containing ROM files, but they certainly aren't difficult to find.