The Wii has a Virtual Console. Lets you download games from the NES, SNES, Master System, etc. No Game Boy, though. Why? Maybe because they were saving those for the new Nintendo DSi.
A rumour on game site Kombo says that, at a recent event for Club Nintendo members, it was announced that the DSi would be getting its own Virtual Console, from which you could buy Game Boy & Game Boy Advance titles.
These would be saved to an SD card (which the new DSi supports), and limited - at least initially - to first-party Nintendo titles.
Nintendo will only respond with their usual "Nintendo does not comment on rumors or speculation" line, so what do you think? Would you rather pay for a downloadable copy of a Game Boy game and play it on your DSi, or track down the original cart and play it on your DS?