Google for Business Educators has several high-quality materials for free on their site.

Here is an easy way to view them online: Scribd.com

Here are some notable texts for download:

Analytics textbook (pdf)

Google Analytics a Powerful Tool for Marketers

Marketing and Advertising (pdf)

MarketingAndAdvertisingUsingGoogle(2)

Google print, radio and television advertising (pdf)

Google AdvertisingOffTheInternet(2)

IntroductionToNewInternetMediaAdvertisingAndTools(2)