In a post that came into one of my autoblogs: Using Google's Wonder Wheel in Keyword Research I was introduced to a feature in Google of which I was not aware. I hope that many of you were not in the dark as I was, but if so this will shed some light on the subject.
The Wonder Wheel is accessible from the search results page. Enter your keywords in the search box as usual. In the left nav column you can find the Wonder Wheel if you expand enough options. As explained in the article this is a quick and easy way of finding related keywords to your search and building a keyword list.