I posted on this site a few months ago while i was developing an app using particles. Although I did not use your code I learned a lot from your tutorials. It helped me release my first iPhone App, a puzzle game called Galaxi. Galaxi went on sale today.

You can check it out at:
itms://itunes.apple.com/WebObjects/MZStore.woa/wa/viewSoftware?id=334182885&mt=8&s=143441

Thanks for all your help,
Ricky