page rank is an indicator of how "important" google thinks your website is. the correlation between
PR and your search engine rankings is not clear cut (i.e., you can rank higher for specific keywords than others, even though their
PR may be higher. as others have said,
PR may be very important to you depending on the goals of your website.
if you want to increase your
PR, then you must increase the number of backlinks to your site. the
PR algorithm is related to the total number of incoming links, the
PR of the incoming links, and the total number of links on the page that is link to you (e.g., a link coming to you from a
PR 3 site that has only 10 links on it is more valuable that a link coming from a
PR 3 site that has 100 links on it).