It's happening again: Google (re)calculates PageRank for the pages in the index. From what I've seen, only new pages get a PageRank, those that already have one don't get an update. At least for the moment. Google will definitely update PR for all the pages, but they've started with the new pages first as they have fewer backlinks.
A great site where you can check the PageRank of a page is Live PR. The site shows you the rank from many Google data centers and it uses Ajax for that.
Although the value of PageRank for webmasters has been decreasing, a PageRank update it's still an exciting event. The last major update was in February.