Google is in the midst up updating pageranks across their datacenters. Yes Google pagerank is not the holy grail some used to see it as still it is a very easy shorthand to get some idea of how much significance a page has. In concept it
You can track the progress using SEO Chat's tool. We moved our management blog from blogger (where this is hosted) to a wordpress blog a few months ago. It is nice to see that the new pagerank for our management blog is 5. We seem to have no trouble getting pages with pagerank of 5 but getting to 6 is rare. The lowest 5 site would also be nearly 10 times less than the highest 5 site (so the single pagerank number is a very rough guide indeed).
Pagerank is a logrithmic scale (so a pagerank of 6 is 10 times a 5 and 100 times a 4). Still it is surprising how easy it is to get to 5 and how difficult it is to get to 6.
Original paper by Lawrence Page, Sergey Brin, Rajeev Motwani and Terry Winograd: The PageRank Citation Ranking: Bringing Order to the Web.