Corona SDK Approved for Nook Color App Development
The tool allows you to write cross platform applications for the iPhone, iPad, Android or Nook. If you go to the article you will some really well done You Tube videos on the tool. It looks like an amazingly easy way to develop applications, especially compared to objective C.
You can download the Corona SDK and use it all you want for free. Once you have an application developed, you have to pay a $199 per year subscription fee to distribute the app to one platform of your choice (iOS or Android). To distribute to both it costs $349 a year. For the Apple side you also have to spend $99 to join the developer program. Probably a pretty good price if your app is at all successful.
Corona SDK is definitely worth a look.