Visualboy Advance 

VisualBoy Advance is a Gameboy emulator for Windows. It also has a version for Mac OS X. The good thing about this particular emulator is that it not only supports the regular Gameboy games but also the newer Gameboy Advance games, all in a single interface.

For emulating both platforms, VisualBoy Advance requires that you download the Gameboy Bios and link the application to it. The games are downloaded in the form of ROM files, which are a dump of the game's cartridge. The application itself consists of a single window. The window will automatically resize itself when a game is loaded, but you can change its size from the settings and via the assigned hot keys.

Most GB games are small, so you will have to either put up with playing in a small window or resize them and lose some quality in the process. VisualBoy Advance has really got the whole emulation process down. The games play great and there are plenty of options for customizing video and sound. For instance, you can accelerate video playback to up to 3 times.

The package is completed with support for cheats and with the ability to use joysticks, and record both audio and video.