I came across this interesting read over at http://www.seobook.com/overture-adwords.pdf and I didn't expect to learn anything new. However, the detail explained for each specific search engine is more comprehensive than any other I have seen. This info covers Adwords, YSM, and Adcenter primarily. Good luck with your future campaigns!
it is nice to have a look on what it does to get high expert on SEO. Adword is the best program to advertise but to get success with it is not an easy way though we spent some bugs.