I mainly use Google toolbar to get the correct PR of a page. I also searchstatus addon in Firefox also to the page PR. But you need to visit each webpage to know its PR.
Find them by looking at high ranking sites for your primary keywords. No one said it's going to be easy. The best links usually take a lot of work. Many people focus so much on manual link building they don't stop to see the benefits of having high quality content or having a link-worthy page/site. Look up link bait and research it. You can also search for high PR "dofollow blog" posts. But don't let anyone fool you, there is no such thing as a "dofollow link." Find high PR blogs in your industry and ask to be a guest author. That's a great way to get legit links that are quite alright in Google's opinion.
The first step is to download the Firefox addon, SEO for Firefox, a fantastic tool that will show you, directly in your search results list, valuable SEO information about the pages your search has returned. This information includes PR, the number of backlinks that page itself has, and age of the site. Once the addon has been installed, you’re ready to find some high PR target pages to add your backlinks. Pick one of your favorite do-follow forums or blogs - if you don’t know of any you can start with my favorite web developer’s forum, Digital Point. Go to the Google search engine and make sure your SEO for Firefox addon is turned on. Then, do a search for the phrase “site:forums.digitalpoint.com†of course replacing the URL forums.digitalpoint.com with whatever forum or blog you plan on using. As your search loads, the SEO for Firefox addon will show you the PR of each page indexed on the site, while the Google results will show you how many forums posts are on the page.