If you are sending one email to mulitple people just type all there addresses into the to box.
If you are sending multiple emails to 1 person just highlight all the emails and then click forward
Down the left go to People (Two blobby people) across to all contacts. Uncheck all those you don't want to send to. Then across far right send E-Mail. New window will Open then add subject etc... under all those names you're sending to.