A
PR=0 is not necessarily a 0 - it is less then 1.
PR is on a log scale - if you only have one link that Google knows about and you have no penalty, your
PR is >0. Also note that the publically available
PR on the toolbar is only updated periodically, so for some sites what you see may be meaningless (Google takes links into account internally, before they are publically availale via the toolbar)
Oman is right - Link Pop's tool gives you the back links from several engines --> gives a better picture.
If you competitors are
PR 0, they should be easy to beat. Just match there keyword density, location and prominence and get more some links (preferabbly with the keyword in teh anchor text) to get your
PR up --> you beat them.
CBP