Is it possible to download software for the Nintendo DSI to play emulated games?

I found it easy on a computer, but what about on mondern game systems like the DSI, PSP, Playstation 3 and Nintendo Wii? Because these systems can already download from their own sponsor. I guess the question I should be asking is, does this software exist? I have the DSI and would love to play Shining Force II on my DSI. In fact, I'm using the DSI to send this message.

Well you can run emulators on PS3 and wii. Ds original can run them too with a r4 or flash cart. But DSi cant run it yet. For wii i recommend going to wiibrew.org.

PSP can run tons i dont have one personally but i know it can run psx games full speed