Android

Android is the leading open-source Linux-based mobile telephony platform. Originally developed by Android Inc., a startup which Google purchased, Android was open-sourced and released by Google and the Open Handset Alliance. Now you'd be hard-pressed to find a major handset maker that is NOT using Android for some of many of their handsets.

Of course my big item is the Android Cookbook. But there is lots of other information on Android as well: