microphone power circuits
Friday, March 3rd, 2006http://www.epanorama.net/circuits/microphone_powering.html
includes your basic 47 kOhm resistor on the hot line to power an electret capsule from phantom power.
other reasons to visit: circuits for battey powered electrets, “plug-in” powered (eg minidiscs), phantom powered… and great ascii-art circuit diagrams.