OK so this one is a bit sneaky and not that well know but it works great when it comes to getting a boost in rankings
You Can get High Pr Back links from Alexa.com by searching for you site in the Alexa Index and then adding a back-link (just like the ones on this site) somewhere on the web to that page.
Below are some examples of Alexa Profile Pages
Example Profile Pages on Alexa.com
The above links will hopefully get spider-ed by the search engine crawlers, and the resulting backlink from Alexa should give a much needed boost to the domain in question. You can do this with your own site to give the rankings a boost from a high pr site.
One of the best things about using this method is that the links are do follow and it is unlikely that your competitors are doing this so should give you a bit of an edge over them.