I own - http://www.yomuzik.net . I have PR 3 . How to profit from PR 3, I mean - I don't see any difference since PR 0 . Thanks
You could sell links... to pass around your link juice. Otherwise, PR doesn't mean much. Better to focus on SERPs instead.
PR is not going to bring cash for you because many high PR sites might not be among the top ranking sites in Google index. You need to work on your site from SEO perspectives for having visitors and then you may begin thinking of monetizing your site.
Get a high quality content and you'll come up in many results then your PR will help you being in the first page / result.
big PR is good mostly for your ego(and probably for google's ego too) good content -> many visitors -> cash $$$
Don't sell backlinks. Your PR will fall steadily. Not sure how the big G knows but my site crashed from a PR5 to PR0 when I started.