If you back up to iTunes you can restore from iTunes. And if you have archived backups in Preferences you can restore any of the backups, current or archived.
I just did this yesterday. I got a warranty replacement phone, connected it to iTunes and activated it. iTunes recognized it was a new phone, and gave me the option to restore my backup. This took less than 5 minutes. It then synced my music and apps. When everything finished my new phone was identical to my old phone.
One note for desanantonio - you should also save your Camera Roll photos to your computer for extra security. If you connect the phone to your computer the Camera Roll will appear as a digital camera, and you can copy the photos to your computer with any photo management app or just by dragging from Explorer in Windows or Finder on a Mac.