[rrikhy]

Steve blank's blog is a virtual treasure trove of these insights. www.steveblank.com

Eric Reis takes Blank's CD model and extends it into actual product development...where the discussion is much less "Why?" and more "How?" www.startuplessonslearned.blogspot.com

You can also get Steve's book on Cafe Press and Amazon. (can't get it at B&N or Borders) http://www.cafepress.com/kandsranch http://bit.ly/1m4R1S

[bravura]

I second the above recommendations. Read these blogs religiously and prepare to have your mind blown.

You can also join the lean startup circle on Google Groups, and watch this Steve Blank video: http://ecorner.stanford.edu/authorMaterialInfo.html?mid=2056

Four Steps To Epiphany (Steve Blank's self-published book) will teach you something new every paragraph. Buy it. The only complaint is that the publishing is cheap, and your highlighter marks will show through the thin paper.