Pre-orders are for consumers at $70 and ship this winter.
The idea is to give all the hackers maximum access to create awesome apps and then deliver a healthy shiny ecosystem to the consumer. Also, we'd like to see a larger shift towards people creating things, so encouraging early adopters to get aboard the coding train is a positive trend.
It's a huge new interaction space, and we're looking for innovators to explore it!
Other people have asked about openness… will there be any kind of control over what programs can use it (i.e. do they need to be approved by you guys to work?)
Well, that's a big turnoff for a dev. Why instead of maximizing the short term profit you concentrate on the long-term and make this system open with certain limitations to assure your business?
As a counterexample, Emoviv gave a TED talk a while ago showing off a headset that lets you control your computer with your mind. When you visit their website you discover that you can only develop with a $500 “developer edition” headset that comes with a single, nontransferrable license to use the SDK (additional licenses are $99). The consumer model of the headset only runs approved applications.