I don't believe I had seen this written in my short period time in here, or maybe it is somewhere in the archive, but a good solid method to get a high PR is through Feedburner's network program. Feedburner offers groups of blogs to unite under a network of blogs, so you have more power as a group. The good thing about it, is that you can join bloggers who have a high PR (hopefully) in your niche. With this I got pretty quickly my PR 4. Hope it helps somebody.