Before I start this tutorial, I would like to give full credits to crimsontwo from xSellize forums and joshua.menke from cocoaforge. I merely improve on crimsontwo’s work.
In the thread, Gmail + push on iPhone w/ Prowl on xSellize forums, crimsontwo gave instructions on how to run the Prowl python script on your iphone. The downside to it is that if your iPhone connection change from EDGE to 3G or 3G to Wifi or any vice versa, the script will be disconnected from Gmail. To solve this problem, he recommends you to upload the script to your own web server instead.