Jailbreaking/Emulating on an iPhone 3GS

I currently have a 3GS, 16 GB, white iPhone and I was wondering if anyone had an in depth guide for emulating GBA/DS games on it (Pokemon Gold/Silver/Crystal, B/W B2/W2).
Personally I'd like to do it directly off my phone, instead of modifying files on my computer.
Anything that won't break it or won't erase my music.
Videos encouraged!

 

I used gpSPhone to play all my Advanced games. You just need to search it on Cydia. (Assuming you're already jailbroken.) There's a gb colour emulator on there as well, just search it.

I followed this guide: http://www.youtube.com/watch?v=_jrYue-0KYo