Emulation/Nintendo DS

About the Nintendo DS
There are significant software and hardware differences between the original DS / DS lite and the DSi. The DSi features a processor twice as fast as the prior models, and also sports four times as much RAM.
Nintendo DS Emulators
melonDS
melonDS is an open source and performant Nintendo DS emulator. Supports DSi games, microphone input, and local Wi-Fi emulation.
DeSmuME
DeSmuME is a popular Nintendo DS emulator. It is open source and runs under many operating systems.
DraStic
DraStic is a proprietary (closed source) Nintendo DS emulator. Available on Android, it costs money to buy.
No$GBA
No$GBA is a freeware (Gratis) Game Boy Advance and Nintendo DS emulator. Supports DSi emulation.
Hardware Considerations
It may be best to use a device with a touch input for Nintendo DS emulation.