Last year we built a couple of Allegro Current sensors in to our robot. If you'll recall we actually got some current sensors in the KoP, along with some nifty little circuit boards to mount them on... oh... about five years ago, I think.
http://www.allegromicro.com/en/Produ...sors/index.asp
This gave us real time feedback to an analog input on the control system, and allowed us to do PID control on the current to ensure that we did not exceed a maximum current draw.
I guess you can do this directly with the new Jags, but getting a few current sensors from Digikey is a cheaper way to go about it.
Jason