http://www.andrewmurrayhq.com/opkiller
Watch this video to see the simplest way to add a landing page and sales page theme to your main blog theme - plus examples from http://www.andrewmurrayhq.com/a/keyword-domination and http://www.mamanetworker.com
Here's the them I talked about in the video:
http://www.andrewmurrayhq.com/opkiller