Well, I'm pleased to report that I've managed to get the PlayStation Eye (£15) webcam up and running with the Kinovea video analysis package (£0). The advantage of this camera is that it can be run at 60fps which makes it far better for looking at quicker movements.
With this very cheap and cheerful setup I've managed to be able to get the tracking to work fine up to a cadence of about 80-85rpm which is perfectly adequate for my purposes, sample footage below. There is a slowed down version available on YouTube here.
Random musings of a UK based cycling coach. In July 2010 rode the entire Tour de France route starting and finishing 3 days before the pros came through, particularly interested in power based training. Other interests include technology, video recording and editing, photography, sailing, the outdoor life and pretty much anything else!