Google's head of web spam, Matt Cutts, has announced that updates to PageRank will be visible in the coming days. Cutts also said that some existing penalties will be expired with the update.
If you're new to search engine marketing and want to learn about PageRank, here's a whole slew of posts to get you in the know:
Google PageRank: Simplified
Google PageRank isn't the Same as Ranking in Google
Should You Join the PageRank Hysteria?
Thankful for PageRank Updates, Blended Search
The Art of Sculpting, or There's Nothing Wrong with Knowing SEO
Google Will Bank on VisualRank - PageRank for Images