I think Sonic and Knuckles should switch voices kinda....And I've hated Omochao ever since.
Anyways,
1. Go on Wii shop channel and go to " Wii channels"
2. Download Nintendo Channel on your Wii
3. Go on Nintendo Channel, go to "Ds demos" and click "Sonic Colors"
4. Use your DS and go to "Ds download play"
5. Wait and press "A" to play it
6. And then, you can play Sonic Colors demo on your DS!
Have fun!