I have been using a spreadsheet I created to estimate the power necessary to reach a certain speed. I finally put it into an online form so others can input their data and estimate how many watts and amps you will need to go a certain speed. This is similar to Brian's speed calculator, but mine starts with a target top speed and it calculates how many amps and watts you'll need. This is the first version and it is in beta. If you see any problems let me know.

I have been able to get some pretty accurate results comparing experimental data and the theoretical calculations.

The one thing I don't like is the way it outputs the data. It puts the data into a table. I'm not sure how to show the results from just your analysis. I am working on it.