You can either use one of the fake PR detection tools (search for them - there's a lot out there) or simply check the cached version of the page. Type cache:site.com/page.html and check what you get.
some times the checker we get from google is not detect fake PR. the most powerful tool i have ever seen is checkpagerank.net. It will detect whether the PR is true or not
Oh the PR can be wrong eh,how come this has been done! This is the first time I am hearing this..wow things are very creepy
Check out the links which have caused the PR to exist.....are they from only a few domains? If so, what do you think happens when all of the domains are sold to different people?
Check with http://www.build-reciprocal-links.com/fake-rank-checker/ and you will find if it is fake pr or not.