The Google Classroom is a term coined by Google techies in 2009. It refers to the use of various google applications with students both inside and outside of the classroom.
Examples of Google Applications include:
Google Earth -
Google Docs -
Google Sketch Up -
Google Calendar -
Blogger -
These are the most popular google applications to date, but it is the combination of the google applications that makes them more powerful as a learning tool.
Examples of other applications can be viewed at

Google Labs have many apps that are very useful in your classroom and useful for you:

Quick Research Tools:
Public Data - - web2.0 graphic search engine
e.g. Population past and projections - China, India, Australia and Indonesia - Swirl - - image search engine
e.g. Science and Technology search - similar to wonderwheel but with images

Google Squared - constructs a quick research grid -
e.g. Teaching Strategies - Trends - - a comparative search engine investigating popularity
e.g. A search looking at Australian Curriculum and the QSA -,+qsa&ctab=0&geo=au&geor=all&date=all&sort=0

Google Wonder wheel -
A spider map search engine to allows the user to find information in a different format

Posters for the classroom: