Mac OS X on CD
According to Go2mac Mac OS X will be availalble only on CD for $20:
The biggest announcement of the Expo will be the historical public beta test of Mac OS X. The first publicly available version of Apple's modern operating system will be given away for free to keynote attendees on CD-ROM [Hint: look for a ticket under your seat] and it will be available for ordering from the Apple Store for $20 plus shipping and handling.
We'll find out for sure soon enough...