You should have recieved instructions and a form to submit to the rebate processing center. Have you sent in your form with the reciept and barcodes off the box?
You can visit this page to pre-submit your rebate online, and track its status once you've mailed it in. You should also be able to download the form if you've lost it, or didn't get it in the first place.
If you purchased the phone in store, the rebate form and all the steps you need to take should have been among the paperwork you were given at checkout. Our local store has always been excellent at making sure we had all the forms and receipts and papers needed to get our rebates.
If you ordered online, then the stuff should have been in the box you received - with instructions on how to get the rebate.
For mail in rebates, yes, you are supposed to submit barcodes from the box containing the phone's identifying ID #'s and your receipt. Make copies of EVERYTHING, and it usually takes a month or more to get the rebate....