Yes.
Hook up your iPhone 3gs and complete the sync either to iTunes , iCloud or both.
When you go through Setup Assistant on a new device using iOS 5 or later, choose "Restore from iCloud Backup" and enter your iCloud account and password. You will see the three most recent backups for each of the devices on which you enabled Backup. Choose from which backup to restore.
If the home screen icons appear on your device and you wish to restore from an iCloud backup, erase your device (by going to Settings > General > Reset > Erase All Content and Settings). When prompted to set up as new or to restore from previous backup, select Restore from iCloud Backup. Enter your AppleID and password when prompted.
A useful link all about it.
http://support.apple.com/kb/HT1766
http://support.apple.com/kb/ht4946
