Just bought an asus m51sn b1 laptop and it does have a built in microphone, but I'm not sure where. I did look through the manual, which says nothing about it. Maybe it's in the speaker enclosure? Any help?

http://www.notebookreview.com/default.asp?newsID=4381

Let's take a quick tour around the port offerings of the M51:

Front side: Wireless on/off switch, lid latch release, microphone in, headphone out, USB, and 8-in-1 media card reader.

Okay, but I get sound in ventrilo and skype without plugging any external microphones in. Is it using my speakers to produce sound and using them as a microphone?

I think so because my uncle has a lappy too and i can talk with it without an external microphone