This is the official Google Android site for developers. Here you will find all the documentation you need to develop rich android applications.
You will most likely visit this site often.
All tutorials and sample code are credited to their respected owners.
Portions of this page are reproduced from work created and shared by the Android Open Source Project and used according to terms described in the Creative Commons 2.5 Attribution License.
This topic includes some really good links and Android Development resources.
Google Android Design Packages
This page has a lot of packages from the Google Android people. These include: ActionBar Icons, Menu Graphics, Stencils and more.
Android Fireworks PNG Stencils
This page contains Android Fireworks Stencil Art images.
This page hosts the Holo Photoshop Designs and Sources
Ice Cream Sandwich introduced a new type family named Roboto, created specifically for the requirements of UI and high-resolution screens.
This link contains the Roboto Documentation (.pdf format).
Android design color swatches.