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Mozilla has their own beta version of the Google toolbar available on the Mozilla site.
As for page rank, it is important for this reason: If you have a search term, let's say "pig's feet", that you want to lead to your site that sells pickled pig's feet, then the page rank determines where in a Google search your site will appear. So, assuming there are 100 sites that are targeting that term and assuming you have a page rank of "2", the odds are your site will be buried way down in the search return pages. Everyone knows that nobody bothers to look much past the first page of returns. On the other hand, if you have a site Page Ranking of "7", for example, that same search for "pig's feet" will likely turn your site up as one of the top three returns on the first page.
That's why PR is important.