A while ago I did a post about the Pharisees. You can read it here.
I've think that we tend to misunderstand the Pharisees, and what Jesus wanted us to learn from them. I think we are quick... too quick... to label others as Pharisees, without realizing that we ourselves carry many of their less favourable traits (I'll include myself in that).
Today I read this article... also about Pharisees. It brought out some points I found really interesting. It doesn't necessarily answer the question entirely of who the Pharisees were, but it does deal with a common misconception of them. You can read it here. Enjoy :].