If you’re worried about transferring contents from your old iPhone to your shiny new iPhone 4S, then don’t worry as Apple has you covered.

Apple has a nice knowledge base article on this subject. All you need to do is follow these steps to transfer content from your current iPhone to a new iPhone:

1. Make sure you have the latest version of iTunes, which is currently iTunes 10.5. You can download the latest version of iTunes from this link. Please install it after you download it.
2. Connect your current iPhone to iTunes and sync it. Verify that your original iPhone is backed up. For more information on how to do this, see iPhone: About backups.
3. Connect your new iPhone to iTunes (on the same computer you used to back up your current iPhone).
4. iTunes will ask you if you want to restore from a backup or set up your new iPhone as a new phone. When prompted, select the backup of your current iPhone. If iTunes does not prompt you to select a backup to restore when you connect your new iPhone, use iTunes to restore iOS on your new iPhone and try this step again.
   Note: During the process of restoring your old backup to a new iPhone, you may see the iTunes progress bar pause. If this occurs, please allow for additional time for the upgrade to complete.
5. After iTunes finishes restoring the backup you selected to your new iPhone, the iPhone will restart.
6. When your new iPhone appears again in the iTunes window, select it.
7. Click the tabs (Music, Photos, and so on) and verify or change the items you want to sync.
8. Click Apply to sync your new iPhone with iTunes.
9. Verify that your saved SMS messages, email accounts, passwords, photos, notes, and other personal settings are present on your new iPhone. Note that you will be required to enter your email account and voicemail passwords again. If you do not remember your voicemail password, you can reset it.

Note:

If saved SMS messages, email accounts, photos, notes, or other personal settings are not present on your new iPhone, then restore-from-backup may not have been successful. In that case, verify your current iPhone is properly backed up (see step 2), then use iTunes to restore iOS on your new iPhone and continue following these instructions at step 4.

This guide is also applicable if you are planning to switch from an older iPhone to iPhone 3GS or iPhone 4 as well.

We also feel that it is better to update your current/old iPhone to the latest iOS software update – iOS 5 so that you don’t hit any compatibility issues while transferring data using this method as iPhone 4S will come pre-installed with iOS 5.

If you’ve backed up your data to iCloud that was launched yesterday then it’s another way to transfer contents from your current iPhone to your new iPhone 4S, but it would be a lot more time consuming so we prefer this manual process.

Hope this helps, let us know if you’ve any questions.

[via Apple]