Android is a OS targetting mainly smartphones. Soon we may also see netbooks and settop boxes run Android.

Android sits on top of Linux, but in the Android space where the applications run, there's not much to see of Linux anymore. It's a (technically damn good) Java sandbox environment (mobile carriers love sandboxes where applications can't do weird things) where all Applications are written in Java. As a result, applications just work, no matter on what platform (N8x0 or smartphone) they run. The most popular device running Android so far is the T-Mobile G1 smartphone.

The N8x0 Android port is based on the Android SDK that is available for free. It's different from what you get with an official Android device because some applications are missing, and you cannot access the Android Market for downloading or buying applications.