How Long Does it Take for PageRank to Show?

[mike2010]

I notice now that PageRank doesnt seem to work as immediately as it did in the past.. A year or so ago, i could link one of my high page rank sites to my low page rank sites and , and the pagerank would increase almost within the hour.. Is it just me or does it take much longer now?

I have like 8 different sites with a PR of 7 or higher linking to my site of PR 3..and nothing has happened for 4 days now.. Both sites have been cached by google too on a daily basis.. If someone could shoot me an article about how pagerank works now that would be great...or maybe its just me thats having this problem? any info would be appreciated.
thanks
mike