On Friday plenty of people survived a problem “their rank checking toolbar not working” and all were thinking that how long it will continue. Well Google things about its users a lot there for it has retrieved the page rank.
The issue was not with the toolbar page rank actually Google had made a slight ;change in look up URL for the page rank value.
David Naylor sorted out the issue and said that they changed the lookup URL.
Now some of the toolbar have been updated few are left, but they will also be updated very shortly till now you can check your ranking with SEO For Firefox , internet explorer etc.