PageRank is a relative measure of the popularity of a website, especially its value as a link. Inbound links, which are extremely important to search engine ranking, can be compared by their PageRank. For a typical eCommerce website here in Guthrie, a PageRank of 3 is very good. A PageRank of 1 or 2 means that Google knows you're there and you are probably going to move up if you put in a little extra work. If your PageRank is 0, you have a a fair amount of work to do. There is some debate about how much the value of PageRank really matters, but it should not be ignored.
You want inbound links from websites with PageRanks at least as high as yours.