We're seeing a Google Toolbar PageRank update that happened about 20 minutes ago (July 29, 2009). Many of our top level pages have jumped in rank as a result of this latest update.
Also, our take is Google has started to update Toolbar PR more and more frequently. By my count, this is the fourth update in 2009. Note that in all of 2008, there were a total of five PR updates. So if this latest TBPR update is confirmed, Google is clearly updating more frequently and we should reach seven or eight updates by year's end.