PageRank Checker is a WordPress plugin by jasoncaidev that automatically displays your real pagerank with an icon.
The pagerank icon is running code from http://www.websitechecker.info to generate. Visit http://www.websitechecker.info for details.
PageRank is a link analysis algorithm, named after Larry Page and used by the Google Internet search engine, that assigns a numerical weighting to each element of a hyperlinked set of documents, such as the World Wide Web, with the purpose of “measuring” its relative importance within the set.
Download: http://wordpress.org/extend/plugins/pagerank-checker/