Getting started with Android Development
Android Design Guidelines from Mutual Mobile
Visual guide to Android UI widgets
Android App Developers GUI Kits, Icons, Fonts and Tools
Android developers UI tools & templates. Incudes icon sets, fonts, wireframing tools.
Mobile Interface Development: Ultimate GUI Toolbox for Android, iPhone, iPad, Palm Pre
Approaches for developing more effective user interfaces in Android applications - Android UI Development: Tips, Tricks, and Techniques. It is a video presentation from 2 of the Android UI Toolkit team at Google.
I am coming from iOS, so liked Android Vs Iphone Differences (video)
Android UI Development from Android Bootcamp
Android UI Development: Tips, Tricks, and Techniques. From 2 of the Android UI Toolkit team at Google.
Tips, Tricks, and Techniques from Google's Android UI Toolkit Team
Wireframing & mockups - Balsamiq
UI development for Android - DroidDraw
Context search for Android developers plugin for google chrome, that allows you to search android related websites for the keyword's you select.
Android API search plugin for google chrome, which allows you to search for and autocomplete classes and interfaces from the Android API
Android has a set of supplemental tools for stress testing, UI, and other elements of coding.
PNGcrush : CLI tool for PNG icon optimisation
OptiPNG : Another tool for PNG icon optimisation, it also has list of related tools, many GUI ones, for various platforms. Includes one for Eclipse integration.