I think there has been a thread on this already (although I can't find anything with search).
But it does look like the teeny tiny speed bumps that Steve was embarrassed to mention during the keynote are going to happen next week.
I guess the knock-on effect is that the G5 PB announcement won't happen until WWDC. Certainly not within a few months of this update.
Glad I gave up waiting and bought an iMac to accompany my G3 iBook rather than hanging on for shiny PB to replace it.