I think that Fast Blog Finder might be a really good tool to find high pr pages to comment on. Which would work really well for backlinking work. It can be found here: http://www.fastblogfinder.com/ I've heard its the best tool out there. It finds all kinds of blogs that you can comment on, but you can sort them by pr. Does anyone use it? I think a lot of the backlink builders do. It must be good, have you seen how much traffic their website gets? And their site has a pagerank of 4. So it must be popular.