The elusive and evasive Google PageRank is a goal-setting milestone for websites. You can influence your PageRank, but you can't control it.
PageRank is a scoring system used by Google to rank web pages against one another for displaying search engine results. Exactly how it works is a method closely guarded by Google, but in the most general terms, the most relevant websites have the best PageRank, and the most devoid of content don't show up on the PageRank map (PageRank 0).
The Google toolbar gives people a tool to find out their PageRank. Firefox and IE can use this toolbar to display a specific page's rank. It is a plug-in offered by Google and Firefox, and needs to be downloaded and installed into your browser to work. Follow the instructions at their sites. Since I'm on a Mac, I can only use the toolbar in Firefox. There is no toolbar for Safari. http://toolbar.google.com/firefox/index.html
PageRank is a non-linear scale. While PageRanks of 1-3 are fairly common and easily achieved, the number of sites qualifying for ranks of 5-10 are exponentially more rare, meaning that exceptionally few websites sit at the top of the heap.
Eclectic Tech has studied how pages get better rankings. Eclectic Tech, LLC runs one site, http://www.kinhost.org/ with a respectable PageRank of 5 (scale of 1-10, with 10 being nearly impossible). Bear Brook Design had no page rank at all before we discussed with them that they needed an HTML-only website parallel to their beautiful Flash-only website.