THis is a little advanced but offers some good in-depth strategy.
<a href="http://smmwhiz.com/2008/01/24/the-art-of-niche-keyword-analysis-for-social-media-marketing/">The Art of Niche Keyword Analysis for Social Media Marketing</a>
<a href="http://smmwhiz.com/2008/01/24/the-art-of-niche-keyword-analysis-for-social-media-marketing/">The Art of Niche Keyword Analysis for Social Media Marketing</a>