You don't need to know so much about PR. This article is good and has all you need to know for now. Good guide on SEO for beginners My SEO own SEO guide My SEO FAQ That gives you reading for a while.
Try this one: http://www.compar.com/infopool/articles/PR-calculation.html According to the table in this page - You will need 16000+ PR1 links to get to PR5. A lot of assumptions are involved like a)50 outgoing links per page , b)PR1 has 18 actual PR , c)Google still uses original PR equation etc