Google Play is offering DraStic DS Emulator (Android App) for Free.

About this Game:

• Enhance the game's 3D graphics to 2 by 2 times their original resolution (this optional feature works best on high end quad core devices)
• Customize the placement and size of the screens, for portrait and landscape modes
• Fully supports add-on controllers and physical controls
• Save and resume your progress anywhere with save states
• Tweak your gaming experience with a database of thousands of game enhancement codes
• Increase emulation speed with fast-forward