Official Android Developers Page
This should be the starting point for any aspiring developer. The site gives updates on the ever-improving Android versions, access to the Android SDK, a comprehensive Developer Guide and the Android API reference. On top of this, there is a video section and a blog section that would help developers better understand some concepts of Android development. The page also shows developers how they can publish their apps to the Android market and enables them to contribute to the growing online community of Android developers.