My app asks the user to fill in and save a form locally. I want him to be reminded 48 hrs after the app has been closed that he has a pending form. Is push notification the only way out? Does it cost money to use a provisioning service?
iPhone OS 4 adds timer-based alerting for apps that aren't running. See here for a brief description. I'm guessing this means that push notifications are your only option prior to version 4.