"Right on their website", but not in any of their marketing materials or during the presentation. It will be interesting to see if they work at all with non-Apple devices.
Update: CNET is providing a little more on this, looks like they will be compatible (but without any buttons on them, it may not be a great experience):
> They all work with Apple's new proprietary W1 chip that's being described as a custom chip that uses ultra low-power Blueooth and keeps the two earbuds in sync. CNET reporter Shara Tibken spoke to Apple reps who confirmed the headphones will work with other Bluetooth devices, not just the new iPhones
Update: CNET is providing a little more on this, looks like they will be compatible (but without any buttons on them, it may not be a great experience):
http://www.cnet.com/news/apple-intros-totally-wireless-airpo...
> They all work with Apple's new proprietary W1 chip that's being described as a custom chip that uses ultra low-power Blueooth and keeps the two earbuds in sync. CNET reporter Shara Tibken spoke to Apple reps who confirmed the headphones will work with other Bluetooth devices, not just the new iPhones