Q:

Writing a game for the Nintendo Wii

I'd like to write a game for the Nintendo Wii. How do I go about obtaining an SDK and/or any other tools necessary for writing a game?

A:

The Wii Remote and Wii Balance Board use bluetooth.  You can pair them with your PC and write your own PC apps that interact with them (like this guy).  If you want to make something that actually runs on the Wii, you can try finding some homebrew development help.
If you want to actually sell your software for Wii, you need:

game development experience
secure office facilities
$2,000 - $10,000 for dev kit (WiiWare is cheapest)

The Nintendo Software Development Support Group
Authorized Developer Application
UPDATE: Also see the Wii U Developer Site. Nintendo now has a simple application for individual developers to makes games for the Wii U, giving you access to the SDK and dev-kits.

A:

You could spend literally thousands of dollars on the dev kit or you could be a bad person and go look at the homebrew stuff. It is technically hacking though, so I only hypothetically recommend it.

A:

If you are a one-man team, then your only option is really WiiWare. At $2000 for the kit, you picked the right console. That's a tiny fraction of the cost of a 360 or PS3 dev kit. 
You do have to have your own business. You also have to get your game rated by the ESRB which will put you back another $2500. Your game also has to be really good. In the end you could spend all the money and time and have Nintendo refuse to publish your game for any reason whatsoever.

