In my application I am implementing the Push Notification Service.
I have a Content Provider server, which contains some products in it.
I have generated the SSL Cli
Very cool guide is posted here: Programming Apple Push Notification Services
And an application named PushMeBaby Mac Os App which you can download and use for sending push-notifications to your devices from a Mac.
APNS will send the push notification to your device as soon as your device will become available. If I've not mistaken your device pings APNS every minute.