Dell is offering a so-called "Windows Vista Bonus", where the bonus is Windows XP:

The Dell channel blog is pointing resellers to the loophole in the Windows Vista license that enables business customers to downgrade from the unwanted Windows Vista to its dated, but comfortable and better-supported predecessor.

According to the blog: "Dell can sell what we've branded 'Windows Vista Bonus' which allows us to preinstall XP Professional with a Vista license (on select system categories). This lets customer's upgrade to the Vista platform when they're ready. And yes, Dell will support both OSs."

Dell's blog points resellers to further information here.

(Via Fark.)