Audio mixing/ conference using Astrisk

hello all,
I want to implement 3 party audio confrencing as far as i read its found that we simply have to add the PCM data together. plz give your views on implentation of audio conferencing.
Also which Source code from astrisk to be used for this applicaton?
Thanks in advance,

Regards,

Rahul

Hi
Meetme is a core component of Asterisk . you can also use app_conference as well.

Ian