Get charge state remotely
There's an app here that allows you to do that according to the description (along with many more things): https://market.android.com/details?id=com.androidlost&amp;hl=en

If you want to code your own application then you'll want to check out this Intent and the two Intents below it (ACTION_BATTERY_LOW, ACTION_BATTERY_OKAY):
http://developer.android.com/reference/android/content/Intent.html#ACTION_BATTERY_CHANGED

And this class which has what the Intent contains: 
http://developer.android.com/reference/android/os/BatteryManager.html

You could have your application pick up the ACTION_BATTERY_LOW Intent and then send a message to you warning you about the status.

I'm assuming you've done some Android development before, if not then get the basics down before coming back and trying to code your battery app.