I use SEO software called SEO elite (You can find the link on my SEO Tools page). The creator, Brad Callen, has written this useful e-book on how to maximize your Google Adwords potential. For those of you using Adwords for your affiliate marketing campaigns, or even if you are using Yahoo Search Marketing (formerly Overture), then this book is a great read. Brad has authorized me to give this away for free, so you can download the adwords made easy e-book here.