google page rank goes from 1-10 (the higher the better. 0 is no rank. Most believe the scale to be logarithmic. In theory PR gauges the relative importance of a page. Benefits derived from higher PR are debatable.
And the more inbound links you get for your page, the higher is your page rank. Notice that PR is really Page Rank, meaning that every page in your site have different PR depending on the quality (PR values) of the inbound links
PageRank relies on the uniquely democratic nature of the web by using its vast link structure as an indicator of an individual page’s value. In essence, Google interprets a link from page A to page B as a vote, by page A, for page B. But, Google looks at more than the sheer volume of votes, or links a page receives; it also analyzes the page that casts the vote,look here http://www.sitelobby.com/?p=15
PR, or Page Rank, is Google's way of measuring the importance of a website on a scale of 1 to 10 (0 means "no rank," often a sign of a sandboxed site). Google does this by counting how many important links point to your page, since people tend to link to sites that have relevant content. The importance of linking websites is judged by how many links from important sites point to them, while the importance of those sites is determined by how many important links point the them, and so on. If it sounds like the web, well, that's because this is the web. Put more plainly, a website which has a lot of important links to it (say, Google) is itself important (and has a high PR), whereas a website that has no important links or just a bunch of links from "nobodies" is not important (and has a low or non-existent PR). So, should an important/high PR website link to you, your PR would go up more than if 1000 websites with a few links to them link to you. On the other hand, if you link to an unimportant website, your PR would go down. This is likened to high school, where hanging out with the popular crowd makes you popular and hanging out with the unpopular crowd is social suicide. Watch who you link to, but don't let it cloud your better judgment. A vegetarian website could link to a popular steakhouse website, getting higher PR in the process, but wouldn't get much traffic. A high PR is not enough, though, as it is analyzed in context. That is, a website's content is considered in addition to its PR. So, a search for "egg rolls" won't place Google at the top of the search engine results page because, content-wise, Google's page has no information about egg rolls. In the end, you should work on building many important links (from websites that also have a lot of important inbound links) and valuable content. --Tony Webmaster, PaidOnlineSurveyCenter.com
Note also that PageRank is logarithmic. That is, every PR point implies roughly N times more links (i.e., N is the logarithmic base). There are different speculations as to the value of N, but it is probably somewhere near 7.