I hope it's like mystery dungeon, in that you can play it on the current platform AND the new one.
It'd be neat if you could, like, put it in the SD Card slot of the DSi, to do a Pal Park-like migration from Hg/Ss
Like a few people, I only really use my DS for pokemon (I got DSi to replace my broken Lite because of it's looks), so I'm not ready to buy a new system yet