Tammy Worcester (GAETC 2008) has compiled a list of Google tools that can be used in your classroom. These tools include documents for student collaboration, form for online quizzes and surveys, blogs for information posting, etc.
See the links for more information:
http://www.tammyworcester.com/Tips/Google_Tools/Archive.html
http://www.tammyworcester.com/Tips/Tammys_Technology_Tips_for_Teachers.html