I have been asked in the past, "how did you control your computer with the iPad?" While working with or teaching classes, I have used my iPad to scroll through presentations or click/open certain applications on the MacBook. To do this, there are several apps that allow you to control your MacBook's desktop from your iPad or even iPhone.
But, Splashtop seems to be the app that provides the biggest bang for your buck. Right now, the holiday season has caused the Splashtop app to come down in price. The current price is only $2.99. Its regular price is $19.99, and I suggest picking it up at this lower price. To allow this app to work with your MacBook, the Splashtop Remote Desktop would also need to be downloaded and setup on your computer. As a warning, though the initial setup isn't too difficult, it can be tedious. Nevertheless, the Splashtop app and remote desktop is worth $3 and the setup time. This app combo offers an easy way to unleash teachers from the front of the room.