Google launched Google in Education at the start of 2012 as a one-stop-shopping location for all things Google Education related. It's recently been updated with even more resources.
Google in Education has all of Google's great resources for education organized by Teacher, Student, and Organizations. The teacher page has Classroom Tools, Professional Development, and Student resources.
The Classroom Tools include Google Apps in Education, educator guides and lesson ideas, and classroom videos.
There are some great resources on here. If you use Google's tools, you should check this site out.
Google's Resources for Educators
Why I Use Google's Products as an Educator.