Google has started PR update from second week of January 2008. From January 10 th onwards some reported that their websites demoted to Pagerank Zero. Some reported that, the inner pages of their websites got good ranks but their homepage got Zero Pagerank. A better example for the above case is technorati.com. Technorati.com is still showing Pagerank zero. But some of the internal pages of Technorati.com is showing Pagerank of 4.
The above cases clearly indicates that google has not finished it's January 2008 PR update. First it has updated Pagerank's of new and some popular websites. PR update is a long process. According to Netcraft report the total number of Websites on Earth is around 156 million. So it is impossible for Google to update the Pageranks of all these websites on earth in 2 or 3 weeks.
I strongly believe that Google has not finished it's January 2008 PR update. For example take my blog. I have started my blog in October 2006. My Pagerank is still 2 since from 2006. But today I checked my blog's Pagerank on Google Data Servers. Most of the Data Servers are showing a PR of 2 but some Data Servers are showing a PR of 7. This clearly indicates that Google will update my PR in the coming days.
You can check your PR on major Google Data Centers at this website.