I'm one of the lucky ones who have an interactive whiteboard in my classroom and it is a very useful tool teaching. It is a data projector connected to a computer, and when you are for example streaming films it is shown onto a whiteboard. To control the computer you are not using the computer mouse, there is a special pen to use. When the pen is activated it is possible to draw on the board in the program you are working with. This program could be a web page, power point, different documents. When you have finished your work it is possible to save the work. You can also use the pen with different colors to highlight things on the board and even move items on the screen. There is a keyboard that can be accessed when you need to type, and then you use the pen on the letters.
On the net you have a lot of interactive programs that can be used on the interactive board. Mostly I have been using my IWB to stream films, but I have made mind-maps on bubble.us together with my pupils. They liked it but they thought I was to slow when using the pen to type on the board. So I have to do more practice the pen.
In the start, there is plenty of time to learn about this tool but when you have done this you have a fantastic tool in the classroom.