ipads in the classroom

     In the classroom I have seen Ipads being used as a teaching tool.  I can see how the teacher would use it to get stuff from their notes onto the screens by connecting it, and how groups could use them for presentations, but how else could they be used?  Could the teacher e in control over what the children are allowed to view?  how intense and often should they be used, so that the children see them and feel special or should they be used as an everyday ocurance so the children get used to them.  how else might these ipads be used in the classroom?