If you are using Internet Explorer or Mozila Firefox You can downloand Google Toolbar and check your page rank there.
Simply install the Google toolbar in your browser, a small box will appear in the browser tool bar. Then simply put your cursor on that box it will show the PR of opened page.
There are many ways that you can check your PR: SEOquake (Google Add-ons) prchecker.info/check_page_rank.php Alexa Toolbar and so on...
There has been lots of different suggestions about checking page rank. There are plenty of website that will allow you to check your page rank you just need to google them. If you use firefox i would suggest getting a page rank checker tool for that and you might be able to view more information about the website plus it would make it quicker to check the page rank of each page on your website as each page will be ranked differently
I installed the google toolbar and find it really useful, i think its only available for the firefox browser though (?)
I use Extensions Chrome SEO. The Google Chrome SEO Extension provides easy access to Search Engine Optimization Tools that can help you with Competitive Analysis, Keyword Research, Backlink Checks, PageRank Checks and other daily SEO tasks.