At Nintendo’s Japanese press conference Nintendo announced a new name for Wii Points, Nintendo Points. This can be used only at DSi stores. The cards will be circulated in all DSi stores at Japan in November. Just FYI the card cannot be used on a Wii or a DSware, just one card and one console.
This means that you will not be able to transfer points from the new device to Wii. This also means you cannot use your spare Wii points from the Wii on your DSi. DSi games will cost 200, 500 or 800 for premium titles. So now, all those spare Wii points can be shifted to the junk yard.