Digital multi-meters work good for current draw readings. You just put them into the circuit, in series, with whatever you want to get a measurement on. Or you get a clamp on meter that can do DC amps.
http://www3.towerhobbies.com/cgi-bin...&I=LXLMV0&P=ML
I also bought a Watt's Up meter. It also goes in series with your load. Pretty cool little device, but I haven't used it much. Kind of a neat little toy to play with. Just to see what kind of load your motors are drawing. It also monitors battery voltage too at the same time.