DeSmuME is the most seasoned open source Nintendo DS emulator. It sports tools designed for hackers, speedrunners, youtubers, and casual gamers. Homebrew programs are supported and can even be debugged through GDB.
The Windows and OSX versions are both relatively feature rich, and there is a small universe of forks and mods that add even more features for casual gaming.
DeSmuME is the origin of RetroArch and OpenEmu Nintendo DS support and is used by several mobile Nintendo DS emulators, with the notable exception of DraStic.
DeSmuME's source code is now hosted at https://github.com/TASVideos/desmume/
It works great and is fast on Pokemon SoulSilver, but I saved my game, came back today and the progress was gone, ALL OF IT, even though I did save a lot of times before, now I'll have to begin again!
I'm currently having a problem with the 9.10 version. It won't load any of the games. None of the FAQs, nor the Wiki has an answer to my problem, and the condescending attitudes of both Wiki and here are not helping in the least. The 9.8 version was easiest for me, but I no longer have it, nor can I access it.
I like this elumator but the problem is it gets stuck in the middle of the game so i can get out of it, even with a saved data
the latest version of desmume will not download. when i attempt to download it, it appears to complete itself; however, it only gives me an error message of "application not found"