Question: How can i make my application start on the iPhone startup?

Answer: 
You asked this question on 10th August 2010.

Now it's 13 November 2012. I'm adding this answer for future people who have the same question.

Now in iOS 6. There is a built in feature called guided access. You can achieve this feature using guided access. Still now you can't do this through code.

Please check these links:

[enable-guided-access-ios](http://osxdaily.com/2012/09/25/enable-guided-access-ios/)

[tip-how-to-turn-on-guided-access-in-ios-6-put-ipad-into-guest-user-mode](http://www.macgasm.net/2012/09/20/tip-how-to-turn-on-guided-access-in-ios-6-put-ipad-into-guest-user-mode/)
You can only do it with a jailbroken phone.