Hello-mobilesubstrate
---------------------
Mobilesubstrate extension and Preference Loader Sample 
A demo project that run on jailbreak iPhone and iphone-gcc

You can get the installation and header file setup instructions here
http://iphonesdkdev.blogspot.com/2009/10/how-to-compile-mobilesubstrate.html

Website
http://iphonesdkdev.blogspot.com/