AIR does not provide any APIs to get at this information. You might consider using native extensions to expose it (http://www.adobe.com/devnet/air/native-extensions-for-air.html)
I believe that Google does not recommend using a unique device ID so what you are looking for might not be simple across all Android devices.
"There are many good reasons for avoiding the attempt to identify a particular device. For those who want to try, the best approach is probably the use of ANDROID_ID on anything reasonably modern, with some fallback heuristics for legacy devices."