My little brother bought a GBA Flash Card, and I was able to (finally) flash my Nintendo DS' firmware a few days ago.
I've been playing homebrew code/games (through WiFiMe and using the flash card) since then.
There are some pretty amazing homebrew developed games so far (notably: Omalone).
I want to start developing for the NDS soon, as well.
I've also flashed Ed's NDS, and the NDS of a friend of his.
They both bought RaLink Wifi cards so they can work with WiFiMe, heh.