There was a confirmed minor PR update happening yesterday. I didn't see any change on the main page, only some of the newly created pages moving up a notch.
One of my PR3 sites which was penalized by Google went up to PR4 yesterday, but there isn't any change in the rankings for important keywords. PR for other sites has not changed.
I've noticed the same but not with new sites - only on sites with pre-existing pages and PR passed to new pages on old site but I haven't seen PR update on sites that are new with new links.