This did not come up on search, so I thought I'd post. Not sure if this should go to Games or here since this is an emulator, not an actual game.
MeBoy 2.2 works on the 5800. I think its made by some guy called arktos (at least that's the website's name)
Quote from Site
"MeBoy is a Gameboy emulator for mobile phones (which means you can use it to play Gameboy games on a mobile phone). It works on phones with support for Java Micro Edition, specifically MIDP 2.0. Your phone manufacturer's web site can tell you if this includes your phone.
MeBoy supports both Gameboy and Gameboy Color games, and with version 2.0 you can even play your games with sound!
With MeBoy you can also save your progress at any time, whether the game itself supports saving or not. Any number of saved games can be stored concurrenly (only limited by your phone's available storage space). Since version 2.0, you can share your saved games with your friends via Bluetooth.
I started working on MeBoy in 2005 after I wondered why there was no way of running Gameboy games on my (at that time) new and shiny mobile phone. Determined to rectify the situation, I started work on MeBoy by porting JavaBoy to J2ME (JavaBoy is a Java-based Gameboy emulator for PCs, written by Neil Millstone). The direct port could only emulate a single frame per second! Lots and lots of optimization later, MeBoy was ready for release. Luckily, it is also getting faster every time a new phone model is released!"
Meboy Download Link (Official Site)Ok, here's a guide to how to use it.
1. Once you download, you will see a MeBoyBuilder.jar file. YOU DO NOT INSTALL THIS TO YOUR PHONE.

2.What you do is to right click it>open with>java binary

3. It will come up with a window with an option to add games.

4. Select your games. Use normal Gameboy ROMs from the net. I get mine from Romulation.net (under the Retro ROMs, there are GB and GBC ROMs).

5. Select all the games you want then click on Make Jar file. Save it to where you want.


8. You install the MeBoy.jar file into your phone.

9. On your phone, in the applications menu, you will see the MeBoy Icon.

10. If you select it, you will see this menu

11. Here are some of the Settings

12. Clicking on "Start Game" will show you the list of games you have. Note that if you want to add a game, you need to go through the entire process from 1-8 again to make a new MeBoy.jar file with the additional game in it. Do not worry as the installed MeBoy in your phone will see it as an "upgrade" and will incorporate it into your phone without deleting your old "saves".

13. Once in the game, select the left onscreen softkey and you will see a list of options (including fullscreen to get rid of the 5800's bottom buttons). Set buttons will allow you to set which onscreen game buttons do you want to represent each gameboy function (up,down,left,right, a,b,select, start).

14. This is how the button setting would look like. After it sets, select the softkey again and select resume. this is also how the game would generally look like. It is also possible to play in landscape mode. Sorry i cant post in-game screenshots. BestScreenSnap doesnt seem to work in-game.

OTHER IMPORTANT LINKS:
MeBoy FAQMeBoy Known IssuesGame Compatibility List----------------------
Subject edited //Usta