Appigo's update to their software "ToDo" was just approved and released by Apple through the iTunes App Store. The biggest new feature, among several other enhancements, is the addition of push notification for tasks. You can set due times for tasks and it will remind you (through playing one of four built-in sounds that sound pretty good) of the task in advance (user changeable). I haven't gotten my first push notification, but I'm pretty excited this finally came out. I've been waiting for this update for a while.