Hi Doug
I just used the 10A limited ammeter built in to my cheap digital multimeter.
Aside from that, if you want to measure higher current, you could possibly use one of the "clamp" style multimeters - I'm sure they have a higher rating than my DMM:
http://en.wikipedia.org/wiki/Current_clamp
Though they don't all measure DC current as well as AC (see the wiki article, link above).