We have posted before about the video-out capability of the HTC Touch Pro, but a video is probably a lot better to show of the functionality. I came across this one while wandering the internet, and it not only shows the usefulness of the feature, but gives a good overview of the functionality built into the HTC Touch Pro (which explains its near 11 min length)
I know if I traveled regularly I would be sorely tempted to buy this add-on. At £16.99 its not even really that expensive.