181 Google Tricks that will save you time in School - updated is an article that has, as it's title suggests, some great tricks for using different Google apps and resources in education.
The tips include improving your search and finding what you need, using Google Scholar, iGoogle, Google Groups, Google+, Google Docs, Gmail, Google Calendar, Chrome and much more.
If you use Google's apps and resources, this is a must read.
Presentation on Google for Educators
Why I use Google's Products as an Educator (and how)