PR has nothing to do with traffic. You increase your
PR purely and simply by getting links.
http://www.webworkshop.net/pagerank.html
You can check your
PR by installing the Google Bar or by checking it with an online tool like this one:
http://www.pageranktool.net/
BUT my 2 cents will be not to worry about
PR but exchange links that make sense in a user point of view.