Android Application Development
For the most reliable reference to the Android Application Development go through:
This includes java doc to all classes, packages, and other variables and is the most updated site.
Though it is most customary to get started in Eclipse, which is the most standard, you are also free to use Netbeans, but the Netbeans updates for the Android SDK plugin is not very dynamic and to my knowledge was developed and supported by a single project called Kenai.
You should also know that you can not step into Android Application Development with out having base on Core Java programming, yes, that is a pre-requisite, else it is bit difficult.
So then, welcome, get ready to jump into the droid community and get going.