Using Google Insights For Niche/Market Research?

Are you using Google Insights for Market Research? Blogger Ben Johnson has a great post on how exactly Google Insights may be used for Market Research. Johnson writes, "So what is Google Insights? Basically it's a tool which allows you to compare and analyse search volume and patterns for your specified search terms over a given period of time, area of the world or a specific category."

Not only does Google Insights allow real-time data, but the clear charts really make it worthwhile for market researchers.

What other free software is available for market researchers? What tips can you share for analyzing the market for a particular product or service?