Excellent article from Search Engine People on how to use Google for free keyword research. These are the tricks of teh trade, people.

Whenever faced with a new client, II like to see who is in their competitor space and get an understanding of the keywords they rank for and where they spend their online dollars. While no report is dead on, the folks over at Spyfu can give you a general idea via competitor analysis. What I like to do is put in my client's website and pull a report of top competitors. From there, I pick the top trafficked competitors and view their information. Great way to find what keywords they focus on. If you have any other tools for competitor analysis, post a comment.