I've had a few clients come to me after leaving other companies because their PR went from 5 to 3, after looking at their linking structure a good portion of it was useless. PR is more used as a benchmark and to leverage the importance of a site by how many times Google checks for updates, if they're checking up more often and level of importance is higher than the faster and higher you will rank.
Same here My Client Websites has also change from PR2-0 and PR1-0 If i am not wrong next PR is in 2010 SEptemeber
I have not seen PR updates on any of my website, but yes two of profile received PR Updates, its seems like google had started to roll on changes