I opened up some $2 Harbor Freight multimeters (that's right, $2 with the coupon) so I can see the current coming in from the panels and the current going out from the battery. Pretty simple and something I've wanted to do for a long time. I soldered right to the back of the meter since the probe leads that come with the meters don't look like they'd handle the advertised 10 Amps.
Overall it's really useful to be able to see the voltage at the battery and the current coming in and going out at an instant. The next step would be another set of meters showing the panel voltage and current then add the power harvesting MPPT circuit and then another two meters showing what's coming out of the MPPT circuit and into the battery.
These Harbor Frieght meters are a great value. If you burn one up you're not so upset afterwards.
Also I got lucky enough to be included a Sparkfun video blog / market resarch thing so supposedly I'm going to be able to keep the video camera they send me. Can't say no to free stuff.