Here's the deal. Dell agreed to Microsoft's plan of allowing Windows XP sales after June 30, but at a surcharge over installing Vista. How much of one? US$20 to US$50. ComputerWorld says that customers who buy the Vostro (low-end) desktops and notebooks will pay this fee in order to downgrade from Vista, which Dell is still bundling in order to comply with Microsoft's rule.
Vista Business and Vista Ultimate—the two more expensive versions of Vista—are the only two available for downgrade, and only to XP Pro. So in order to get XP on a Vostro 1000, you'd have to install Vista Business first, which costs US$99 over the default. Then, you're down another US$50 for the downgrade for a total of US$149. That's quite a kick in the nards, Microsoft. Then again, Vista is fine and should work fairly OK on pre-built machines if you want to save US$149. [Computerworld]