When my Mitsubishi TV bought the farm, Amazon has a sweet deal on the Sony TVs. Not wanting to wait a week for shipping, risking damage, and also use my RZ double points option, I went to Best Buy, who actually were able to beat the Amazon price. It took some creativeness on the part of the sales associate, and about 30 minutes to track it down, but he was more than willing to do the work. Of course, I had to ask for the discount. Most people don't realize that Best Buy will usually give you a discount if you ask. I got them to knock hundreds of dollars off other things I wanted to buy before by just offering to pay a certain price.
Of course, if they are contractually obligated to sell something at a certain price, like with the iPhone, there is going to be very little they can do. Apple isn't going to reduce the price in their store, and they woundn't want the competition.
-jt2