that stinks. I hate when that happens if you buy a product, like some electronic or something. several stores in the US now have a price guarantee...for instance, Circuit City:
"If you've seen a lower advertised price from another local store with the same item in stock, we want to know about it. Bring it to our attention, and we'll gladly beat their price by 10% of the difference. If you see a lower advertised price (including our own sale prices) within 30 days of your purchase, we'll refund 110% of the difference. Our policy applies only to advertised prices. It does not apply to special offers or promotions, including rebates, free-with-purchase offers and special financing."

Delta has a "Low Fare Promise"

Until more competition exists for transatlantic flights between the UK and the US (more competition aside from BA and Virgin), I don't see much happening to lower prices for consumers. It's pretty close to being a duopoly (as AA and BA are alligned). So they compete with each other but not much else. They are doing a pretty good job at not lowering their prices and offering things too much (kind of following game theory).