I’ve discovered, through the Android Dev Blog, this great Android Blog called Mind The Robot
Through all his tutorials, Ivan provides us with a lot of explanation, some good advices and many useful insights of the Android platform. I’ve followed successfully the Android UI: Making a Live Wallpaper (Fire Simulation) tutorial to make an animated wallpaper, great !
Last but not least, if you like, you could also follow some of the Google I/O conferences and other related interviews on the Videos section.
I also love to look twice a month at the charts of Android Versions showing how new platform API are spreading, which can help you choose the API level you want to be compatible with (edit: chart updated in April 2011) :
Since the beginning (December 2009), I’ve decided to stick to Android >=2.0 (API level 5) and now Android 2.1+ represents more than 80% of the active devices (edit: now more than 90% at the time of the chart upload).