MeBoy is a Gameboy Colour emulator for mobile phones. It only works on phones with support for Java Micro Edition, specifically MIDP 2.0. The speed depends on the processor inside your phone, which may or may not be fast enough

Step by step tutorial on installing MeBoy:
1. Make sure you have Java installed on your computer, version 1.5 or later.
2. Download MeBoyBuilder.jar (file attached below). If you are presented with a choice, make sure you select ???Save???/???Save to disk???, not ???Open???/???Open with Java??