Here are a couple of excellent free PageRank analysis tools that can help you estimate your site’s standing with Google.
Live PageRank – This tool gives you a comprehensive chart of your site’s PageRank across multiple Google datacenters. If you’ve been waiting for a hike in your pagerank for a long while – and you see a higher figure in any one of the datacenters it might be indicative of celebration time in near future 
Once you enter your URL in this tool, it shows you your site’s Alexa Ranking and Google Backlinks along with the PR chart. Also displayed are the minimum, maximum and average PR values averaged over all datacenters.
Live PR site also offers a PageRank extension for Firefox which sits in your status-bar and displays the PageRank of any site you’re visiting. However, I prefer the SearchStatus extension which shows both your Alexa Ranking and Google PR.
Future PageRank – Brought to you by SEOTools, this queries the various Google datacenters to check for any changes in PageRank values for a given URL. Usually all data centers output the same value, but if queried during an update, you might get a glimpse of any upcoming changes in your chosen URL’s PageRank value (similar to Live PageRank).
Similar tools in this category:
- Google PageRank Prediction – Future Page Rank Tool at RustyBrick
- PageRank Prediction – Predict Page Rank Predictor – iWebTool
Visual PageRank – This tool shows you the PR for all links on a page. Once you enter the URL, the results will show the page given, along with the PageRank of each hyperlink on that page in form a tiny but nice PR graphic beside each of those links. You also have the option to show “nofollow” and external links. Very useful when you want to figure out what links on your site have a higher Google PR.
A similar script that can be run off your own web-space (and for free) is Webmaster Eyes.
If you require any help in setting up one, feel free to drop me a line.
[...] A little investigation revealed that while, http://www.chaos-laboratory.com is at PR 0, chaos-laboratory.com has silently crept up to PR 2 !! So Google has been indexing the non-www version of my site all this while, while the www-based version has been left untouched. [...]