electrical diagram drawing software

Here's a great little CAD program that's free and can be pasted into MS Word or Excel.

http://tinycad.sourceforge.net/

For testing, we've tried Electronics Workbench

http://www.electronicsworkbench.com/ but found some glitches in its operation (tended to hang up on some simple operations)

Grae

Circuit Maker is a free download, and it allows you to test circuits. This is especially handy for DC circuits that use logic gates with multiple connection points and for circuits that use voltage and current dividers.

http://my.ece.ucsb.edu/bobsclass/2C/Simulation/circuit_maker.htm