*edit* oops. I see Tom posting that it works. I'm certain that it didn't at first, though, and I'm pretty sure it didn't work for a long time.

Re. the USB port on the Extreme:

Personally, I don't recommend the USB port if you're using Windows. It requires Bonjour to be installed, which works fairly for printers but I hate how it handles hard disks. Definitely not a good substitute for a NAS. I've also switched my family's "networked" printer from the Extreme USB to just a shared printer on my computer. It's just easier that way, and my computer is almost always on anyway.