Your Google PageRank tells how important your website is. The importance of your website is gauged by how many websites link back to you. And it is not as simple as it seems. Even the websites linking to you too must have a good Google PageRank. This means the websites linking to you should also be linked to by websites being linked to other, well-linked websites. So in a sense, every website being considered for your PageRank should enjoy a higher PageRank.
The inbound links to your website are counted as “votes”. So the more votes you have, the higher PageRank your earn. You can view a website’s (including yours) by installing (if it is not already installed) the Google Toolbar that resides in the upper part of your browser once the Google toolbar is installed. In the Google PageRank button there is a green bar that ranges from 0/10 to 10/10. As a said, the websites sending you inbound links should also enjoy higher PageRanks (PR). The more links you get from higher PageRank websites, the less links you have to garner in order to attain a higher PageRank.
People have written complete research papers on how Google calculates PageRanks but if you are reading this just to search engine optimize your website, then the only thing worth knowing is that you should get inbound links from trusted websites that get lots of targeted traffic — this is the only thing that matter as far as your PageRank goes.
PageRanks used to be taken seriously a long time back, but not now. They do matter, but not to a great extent. You can enjoy top rankings in the search pages even with a PageRank 1.