Hi all! I'm currently developing a simple service called Pushy with a small group of iPhone SDK and Ruby developers. We've developed a scalable APNS provider server, and we've built more feature and abstractions on top of Apple's Push service to make it more valuable as a potential feature for your iPhone app. We're currently in a free public beta, and if you've wanted to use Push Notifications but have not been able to due to the requirement of having a provider server, give our service a try.
Pushy
Thanks!