We had a demonstration of the Optivote voting system a couple of months back, delivered by Phil Stanley.
It works primarily as a multiple choise voting system for use in groups, similar to the ask the audience system in 'Who Wants to be a Millionaire?', but it is very flexible.
I recorded the two hour demonstration and it is available as a streamed .wmv file, at 512kbps.
Phil seems to have started creating some screencasts, available on the Optivote site, which also might be helpful.