Worried about fluctuations in Google PageRank may be a complete but still, the PageRank values of individual web pages on a site can give you some good idea about the relative importance of these pages in Google.

For instance, if there are two or more pages on your site with very similar content, find the one with highest PageRank and then do a redirect (301 permanent) on the other pages. This may be a slightly vague example but you should get the idea.

Brandon Thomson has created a PageRank Checker service powered by the Google App Engine that lets you calculate the Google PageRank of multiple URLs in one go.

The service can also help you find the Google PageRank of all URLs that are linked from a particular web page.