Learn how to make these core services work for you in the classroom. http://learn.googleapps.com
Then there are the additional services available to schools. This is the mega Swiss Army knife of web apps. With over 60 additional services, there is not much you can't do with Google Apps for Education. Here is a list of a few of the additional services that come with a Google Apps for Education account.
That's not to say there aren't other web services that are great for education. There are! But if you have this Swiss Army knife in your pocket, you'll be ready for just about anything!