To identify each devices uniquely I would like to use the IMEI (or ESN number for CDMA devices). How to access this programmatically?
From: http://mytechead.wordpress.com/2011/08/28/how-to-get-imei-number-of-android-device/:
The following code helps in obtaining IMEI number of android devices :
TelephonyManager tm = (TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE);
String device_id = tm.getDeviceId();
Permissions required in Android Manifest:
android.permission.READ_PHONE_STATE
NOTE: In case of tablets or devices which can’t act as Mobile Phone IMEI will be null.