The Mii channel is not available for the Nintendo DSi.
Chat with our AI personalities
Yes, but it has a different name its called dsibrew and it is extremely hard to download.
If you mean by Wi-Fi, you need to have it and go to the DSi Shop Channel.
Sadly, there's no way to. If you want to restart your entire session with the check mii out channel, you would need to reset the entire console.
You can download games/apps for the DSi via the DSi Shop.
You need to connect to the DSi store, and pay for them there. You can then download them to your DSi.