Here is a simple circuit for Homemade Computer Microphone .only three components require to built this (1) condenser mic (2) stereo jack pin (3)ceremic capacitor of 0.1 uf * non electrolytic and about 1.5 meter single core shielded wire . construct it and enjoy!
click here
http://geocities.com/tpsbpl/computer_mic.htm
TPS

click here
http://geocities.com/tpsbpl/computer_mic.htm
TPS