Sorry, no link. Just read an email from one of our studio directors.
Quote mentions Cnet. Perhaps an article can be found there.
According to reports by Cnet, Microsoft is instituting a royalty policy for all Xbox 360 peripherals. This means that a peripheral manufacturer would have to pay Microsoft a fee for every 360 peripheral sold. This system, which is similar to the deals licensed third-party software manufacturers make with Sony or any other console maker, is unprecedented in its all-encompassing nature for hardware.
Quote mentions Cnet. Perhaps an article can be found there.