I'm trying to make a PowerPoint that could be used within a classroom which has a video clip on then an active text box alongside so the children can type in it as they watch. I'm not experienced with PowerPoint 2010 and so any advise on what to do would be greatly appreciated.
I'm using PowerPoint 2007, but it should be the same on 2010...
From the Developer tab on the Ribbon bar, you'll want to fint the TextBox control. When you select it, you'll see a crosshair cursor that you can use to click+drag to draw your text box. Once it's drawn, right click on the box and select Properties. In the properties window, set the MultiLine property to True, and set the EnterKeyBehavior to True. If you don't need either option, leave them False.
That will give you a box that students can type in. However, the box won't really do anything other than accept some text. It will be up to you to program PowerPoint to process the text however it needs to be processed.