No$gba is a freeware Nintendo DS emulator. It is capable of running commercial and homebrew Gameboy Advance and Nintendo DS games, such as Pokémon Diamond which the latest version is able to run at full speed with no graphical glitches. No$gba stays freeware up to version 2.6, if the user cares to obtain version 2.6a he or she has to make a donation of $2.50.
It was considered by many communities the best Nintendo DS emulator due to the fact that it is capable of running most of the commercial games at full speed and without video/audio errors. It is considered by many to be the first Nintendo DS emulator running commercial ROMs, though others state that's already been countered by reports of successful emulation elsewhere.
The official website for No$gba is here.