SamSoccer7:
There's no reason to address this to Handspring, as they're not the ones handling the rebate, it's a CompUSA deal as far as I know. There's still some controversy around it, but I think it's a Mindspring Rebate center, that has nothing to do with the now non-existant ISP (which was a darn fine one).
As for returns, how would you do that? To return something to CompUSA, you need a receipt from there. If you mean that you bought one from CompUSA, and another from Amazon, and returned the one from Amazon to CompUSA w/ the CompUSA receipt, no, it makes absolutely no difference. But be prepared that they may hit you with the 15% restocking fee for opened items.