There are rumors that the Babies R Us stores will give you store credit for used BPA bottles because it is a safety hazard. Each store can set its own policy regarding this issue.
I called one of our local stores. Their policy is that if you were registered at Babies R Us, or have a receipt for bottles, they will offer store credit towards trading in your BPA bottles for different bottles. Other stores don't require a receipt at all - call ahead to see where you can get the best deal. I bet few if any moms have the receipts for bottles. Sheesh, I can't even find my keys.