As I feel the trust rank does a big influence for the googlebots frequent arrival. There is no place for us to know a certain criteria about the googles behavior and its responses.
Start by going to your Google Webmasters account in the External Links section. Check if the link is already reflected there. Sometimes in as little as 3 days I see the link shown in the webmasters tool, though sometimes it takes a month or so Remember though that backlinks is just one of the factors in Google's algorithms, and any links from a PR5 can be diluted by other factors. Also that it takes a while for Google to update the visible PR toolbar, though they sure have the updated numbers used in their algorithms
It's a matter of how often they crawl the page(s) where your backlinks are at. That's the only way for them to "recognize" those links - most content is spidered again within 30 days, but if the site updates often, Googlebot might visit much, much sooner. As far as when PageRank is calculated, it is updated near daily. The comment about every 3 months is a half truth. Google updates Toolbar PageRank (the 0-10 number you see) about every 3-4 months, and the data is aged. They don't give "current" PR because then it'd be a lot easier for us to figure out how to influence/manipulate PR. So whatever numbers you see in the toolbar are several months old. On a sidenote, one thing you might want to look into is the PR of the page your link is on. A lot of people say that they just got a link from a PR5 site, and while the homepage may have a PR5, the page that the link is on may be a PR0 (or worse, not even exist in Google's index). Now if that's the case, it's nothing to get upset about (especially if it's a new page - its actual PR is likely very different from what you're seeing in the toolbar, as Google keeps up-to-date PR), unless it's on a page that's been around for quite some time and you're paying for the link. If that was the case, I'd probably think twice about renewing that link.
here goes www.google.com/webmasters/tools/ 1) Sign up / Sign in 2) Add your website 3) Verify your website very simple
I Think if u want good quality back links so just publish press releases various press releases sites every week. and create micro site and promote them and put your links for all the micro sites so i m very sure you will have good back links and also rankings as well. Thanks