I saw some new pages show some PR about 2 weeks ago. They went from PR0 to PR5. It reminded me of the old system where Google used to estimate PR based on how many directories the page was away from the web root. Over the past 2 months or so I have consistantly seen new pages stay PR0 (white bar) as opposed to the new PR being guesed.
This makes me thing that PR is still being estimated, but will not be visable through the toolbar until the page has actualy been crawled. Perhaps this is the start of on the fly PR calculations.
One of my pages that has been up for a couple of weeks ranks #1 in some obvious searches. It's been showing fresh dates including July 13. It obviously must have been crawled but no PR on the bar. I'm seeing this sort of thing on other newish pages as well.
Since Dominic there seems to be much more of a delay on showing PR. I guess it's no big deal. It helps to know it appears to be happening this way to everyone.