Not just a search engine anymore; google offers numerous services for its users- tools that have great applications for teachers and the classroom.
Among my favorite include blogger, google page creator (where I curently make and house my class website and team website), gmail, picasa web albums, igoogle, google maps, google reader, and google docs- and that's not even the half the "cool stuff" available.
You can't have any of the fun without registering for a google account though, so if you haven't registered for one at http://www.google.com/ or http://www.gmail.com/ then do it now!
Note: If you are thinking of making a website using googlepages for a team, where you want multiple people to be able to edit the pages you may want to create a generic account with fake names and information so that multiple people can use the information. Yes, this will mean that you will have log in and out of your personal google account to access your team account (which is kind of a pain) but that way team members won't get your personal information.