How To Reset iPhone4 See here

Please Don't Reset iPhone3g And 3GS
When u Reset 3G And 3GS you See only Show Apple Logo not solve this problem with out Flash 
There two option for resetting in iPhone 4

For network resetting: Touch Settings -> General -> Reset -> Reset Network Settings.


For full resetting Touch Settings -> General -> Reset -> Reset All Settings.
Warning: You will loose all of your preferences.