Your IWB software will probably have a large resource library within which there will be lots back grounds and images to use in creative narratives, poetry, etc. If not there is that Interweb thing.

If your white board does not have a built in recorder you can use:
Jing which records as a swf, the advantage to this is it is small in size, web ready and you can narrate as you go. Problem is if you muck up you have to start the whole thing again.
Autoscreenrecorder is another one. Records without sound but you can edit it in windows movie maker and add narration then so it is more forgiving. You can also adjust the file size in the process.

The movie below was made using IWB to make the rocket fly across a blue back ground then we superimposed it on the solar system to make it more interesting. We could have simply used a star background on the board to keep it simple, but why would we do that. If you want to know how to ake blue screen movies go here. The solar system simulation is Universe sandbox you can purchase through steam( $10US cheaper) or have a free demo here.