The following link is to an emulator called meboy. It allows you to play gameboy and gameboy color games on a mobile phone.

It works by loading the roms into the jar file which is then transfered to the mobile phone.

http://www.techagesite.com/emulators%20New%20and%20good.htm

Better, perhaps to link to the Meboy site directly: http://www.arktos.se/meboy/versionhistory.php

Looks like the project may be dead already.