Gmail in the classroom

I can see the advantages to using gmail in my classroom because the current system we are using in my district has frustrated parents and students.  With gmail it would allow me to create groups based on the six classes I teach. I could use these groups to send important information to one class or all my classes depending the need.  It would also be nice to have some question and answer sessions/virtual office hours to connect with students using gmail chat.  By using chat it might help students who might be to shy to ask questions during class an opportunity to ask them in a way that makes them feel comfortable.