Google Classroom is available for schools who are using Google Apps for Education. This tool will allow teachers to setup a virtual classroom environment for their students. Here is a quick video introduction of the power of Classroom.
http://youtu.be/K26iyyQMp_g
Teachers who are using Google Apps for Education must create an account and create a class. When a class is created, a class code is generated. The code must be shared with the students so they can join the class.
Once the students join the class, the teacher can post announcements, manage assignments, manage class rosters and email students directly from within Google Classroom.
Here is a presentation about Google Classroom. Enjoy!