Dell has had so many customers complain about being forced to switch to Vista that they've decided to offer people buying a new PC a choice between Vista and XP. The story I read said some other computer merchants are doing the same thing, but Dell made the news because of how many they sell.
The story also said the folks in Redmond weren't too happy about it, but Dell (and other sellers) evidently do have the right to offer buyers more than one OS.