Can I use unlocked Bell Canada Iphone 4s in U.S.A?

You do need to backup your iPhone. If you back it up to your computer archive the backup.

After you receive your notice that your unlock is approved it will normally say wait 24 hours. After that time restore your iPhone as a NEW phone and you should get a message, "Congratulations, your iPhone has been unlocked." After that restore your iPhone from your backup and you will get everything back.

Thanks Deggie. So there is an Itunes choice to "Restore as New Phone?"

Yes.

Thanks again. This is where I get confused.

Instructions from Apple follow, my comments in CAPS:

Start the process:

1. See if your carrier offers unlocking. Only your carrier can unlock your iPhone. YES
2. Contact your carrier and request an unlock. You might need to meet requirements to qualify for unlocking. After you submit the request to your carrier, it might take a few days to complete. Contact your carrier for the status of your unlock request. DONE AND RQST APPROVED
3. After your carrier confirms that your iPhone unlock has been processed, go to the next section.

If you have a SIM card from a carrier other than your current carrier, follow these steps: DON'T HAVE ONE YET

1. Remove your SIM card and insert the new SIM card.
2. Complete the setup process.

If you don't have another SIM card you can use, follow these steps to complete the process:

1. Back up your iPhone. WANT TO START THIS NOW.
2. When you have a backup, erase your iPhone. UNDERSTOOD THAT THIS USES THE RESET SETTING
3. Restore your iPhone from the backup you just made. NO MENTION OF YOUR ADVICE TO RESTORE AS NEW, OR IS ITEM 2 THE SAME RESULT

Thanks again and hopefully I won't bug you again.

You do have to restore it as a new iPhone if you are going to get the unlock message. If you are using your computer it is not necessary to erase it first.