For at-home use for me and my wife, i use the Slim Guide skinfiold caliper. It's only $25. Not as reliable as expensive models, but probably more accurate than some of the electrical impedance devices. You can find it and other devices at this link:
http://www.topendsports.com/testing/store-skinfolds.htm
After I take measurements, I enter them here to calculate the %:
http://www.linear-software.com/online.html
John, do you think entering measurements from the Lange on the site linked above is just as accurate as using the formula provided with the Lange calipers? I just assumed it was the same formulas, and it saves some calculating on the tester's part.