We already supply the pedalog - a power and energy monitor especially for pedal powered generators. It also works with other forms of energy generation such as solar and wind and also energy consumption of DC loads.
One issue was displaying the data so that it is interesting and informative. One customer (Magnificent Revolution) asked for a large display for use on their multi-bike generator. This would be for use at events where the crowd wanted feedback of how much power and energy they are generating.
As it was for use in the field, wires are always a hassle so we decided to use wireless communications to talk from the pedalog to a remote display. Have a look at the blog posts relating to the technical issues on getting this done. We used XRF wireless modules which have up to 1km range in clear line of sight. These, along with a Xino (an arduino clone) and a nice LED display, allowed us to produce a prototype, shown here.
There are still some things to be sorted out, but its looking great and will be a such a useful asset we are building one for use here at re-innovation which can be used for teaching and our own pedal power events.