nds4droid is an open-source Nintendo DS emulator available for Android devices. It is still in its early stages, but it supports many features such as save states and sound. Additionally, it is compatible with the OUYA game console. Unlike other DS emulators, nds4droid does not violate the GPL, making it a legal and ethical option for gamers.

It is important to note that Nintendo DS emulation is still slow, even on high-end phones, but the nds4droid team is continuously working to improve the software. If you are experiencing performance issues, try adjusting the "frame skip" options. For more information, you can check out the nds4droid FAQ on the developer's website.

Overall, nds4droid is a promising emulator for Nintendo DS games on Android devices. Its open-source nature and adherence to the GPL make it a standout option for gamers looking for a legal and ethical way to enjoy their favorite DS games.