Use a PendingIntent, whose Intent has bundled extras.
This is modified from the AlarmController Google APIDemo:
Intent intent = new Intent(AlarmController.this, RepeatingAlarm.class);
intent.putExtra("some_name", some_value);
PendingIntent sender = PendingIntent.getBroadcast(AlarmController.this,0, intent, 0);
// We want the alarm to go off 30 seconds from now.
long firstTime = SystemClock.elapsedRealtime();
firstTime += 15*1000;
// Schedule the alarm!
AlarmManager am = (AlarmManager)getSystemService(ALARM_SERVICE);
am.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP,firstTime, 15*1000, sender);
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Then retrieve those in your Receiver's onReceive():
intent.getStringExtra("some_name")
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