Are you asking how to replace the screen or just telling us you broke it?

If you need help with replacing your screen, we would need to know which iPhone you have. iFixit carries iPhone 3G Front Panel Kits and iPhone 3GS Front Panel Kits which have all the tools necessary for replacing those screens. We don't carry iPhone 4 parts yet, but they will be available soon.

I hope this helps, but try to be more informative in future answer posts. This makes it easier to give you a useful answer.