Sasha Leitman (firstname.lastname@example.org) will teach how to build a mic and assist anyone who runs into trouble.
This schematic shows the circuit that for these, and an older second diagram shows more detail of our assembly, with a slightly different capsule.
It's best to have the battery near the plug end and a long (3') lead to the capsule.
Test with the mic inputs at any of the computers. They will also accept the quarter-inch plugs we're using. You should be able to see green led activity when you turn up the mic gain. Record some test talking with audacity and make sure it sounds clean.
For further info about this style of mic, see Craig Sapp's page on his site.