C2DM to arduino

Hi guys,

I will like to seek some advice. Currently I am doing a project on arduino. I have a webserver (gae) it is able to connect to an android apk to track device's gps coordinates and send a MSG to be displayed on the andorid phone. However now I got no idea how to get this message to be a command to the arduino so that I am able to get it to activate an actuator hat is connected to it. Please help/advice