I am looking for this also.
I have a microphone and would like to play the output through my speakers. I have a laptop.
I know the microphone is working as when you go through the testing bit of "sound and audio devices" in the control panel, I can hear the output through the speakers with a slight delay.
The choices i have in the playback section of the volume control are: Volume, Wave, Synth, CD Player and Line In. The Recording are: CD Player, Microphone, Line In and Wave Out Mix.
I have only got a microphone input on my laptop and a speaker out.
Is there any way to route the microphone input to the main output on my laptop please? If the is some software to do this I do not mind paying a small amount. Freeware is better though!