What is there to say that hasn't been said by a million others? I might assemble my ideas here. I have a couple comments from watching the keynote below. Otherwise, for now, it's just a few links to bits and pieces straight from the horses' mouths.

• First of all, you must watch the keynote.
• Then read Apple's press release...
• ... and Intel's.
• And if you really wanna tech out, look at Apple's Introduction to Universal Binary Programming Guidelines. I don't pretend to understand it all, but if you skim it, there are lots of good little nuggets in there. For example, Intel-based Macs will not have Open Firmware.

A couple little odds and ends from the keynote:
If there are 2,000,000 Tiger users, and that's 16% of OS X users, there are about 12,000,000 OS X users/installations out there.
"We've got some great PowerPC products still yet to come." -- Steve Jobs, ~24:15 into the keynote.
The transition will take "a few years."
And, my favorite, "Mac OS X is cross-platform by design." Also the revelation that yes, the rumors were true: deep inside Cupertino there have been Intel boxes running every release of OS X--all the way back to 10.0. Smart. But, considering that NeXT ran on (correct me if I'm wrong) 68k, PPC, Intel, and Alpha, it's not entirely surprising.