The question that came to me was:
How can this page has a PR when there the page even not cached. I checked the page with cache: URL in Google and it shows no cache but the page has a PR, the PR is 8, how is this possible? Is it some black hat technique? How can I achieve it?
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Update:
Thanks for the answers but that explains some part of it. Still with all the answers it is not clear as in why caching is not important for PR. It will be great if the answer is put with clear examples.
Answer to the question by Aji (24th April, 2010)
Thats for the great answers.
Let’s see what Google says about PR:
“PageRank relies on the uniquely democratic nature of the web by using its vast link structure as an indicator of an individual page’s value. In essence, Google interprets a link from page A to page B as a vote, by page A, for page B. But, Google looks at more than the sheer volume of votes, or links a page receives; it also analyzes the page that casts the vote. Votes cast by pages that are themselves “important” weigh more heavily and help to make other pages “important”.
PR is independent of page’s status, When A links to B, A passes the PR to B (now B gets the PR irrespective of whether B is crawled, indexed, exist or anything else)

(Source: http://www.mattcutts.com/blog/pagerank-sculpting/)
In simple words PR and Web page existence has nothing to do. I guess you can even have a PR for a 404 page.