PR depends on the link structure of your site. If there are external links leading to your inner page, and that page has outgoing links to other sites -- the PR that you received is passed on to the site you are linking to. Normally, you should have external links to only your Home page which in turn should be linked to other pages in your site and vice-versa. The Home page distributes the PR to the linked pages and in turn receives its share of PR from the site pages. This keeps most of the PR within the site pages. Search Engines rank individual pages--not sites. So if your inner pages have turned up with a PR0-it means your site is leaking PR. You should only have external links pointing to your inner pages if they are more than 5 levels in depth--from the Home Page--because spiders do not index pages that are more than 5 levels deep--but they will follow links from other sites.

Regards
Sunil
http://www.seo-sem-professionals.com