Free single family electrical service calculator.

[gromicko (Nick Gromicko, CMI)]

http://www.nachi.org/bestinspectorscalculator2007.htm

[Greg_Fretwell]

There is an Excel spreadsheet for this too. I got this from the ECN boys

[pabernathy (Paul Abernathy, CMI®, CMECP® Electrical Code Academy,Inc.)]

Got a nice new one also updated on my site -
http://www.theelectricalguru.com/dwellingcalc.xls