Press any app for a few seconds until it starts moving with a slight tremor.
Select the application you want and move it to your liking: up, down, front row, second place or even another screen. To do the latter, drag the app to the edge of the screen.
To create a folder, move an application to another and, automatically, the iPhone will create a folder with the two inside. To change the title just need to click the name field and enter another.
Once you're finished rearranging the icons, press the button 'Home' on your iPhone and see that everything is back to normal ..