Is it possible to add a new icon/button on the main screen for a specific iphone function?

for example, could i create a new icon that brings up the keypad in the phone? or one that brings up a specific web page in safari? or goes to videos in the ipod?

http://www.hacktheiphone.com/iphone_...ification.html

This page has quite a bit of info. I think you take this info and do you own idea if so inclined.