Turn your android device to a wireless set? I would like to know whether there is any app to share audio from an android device to a pc as well as to other android devices connected to the same WLAN network. So that people can communicate to others like using a wireless set without using any mobile network. I know there will be a limit for the range of this setup, but it's not a problem.
Also, I never mind installing any software for this purpose in the pc.
I would like to know what do you mean by 'share audio'? Is it sharing music Files or streaming music. If it is about sharing Music Files, you may use Xender from PlayStore which can send files over WiFi to any other user having Xender installed. For PC, you may use AirDroid from PlayStore to access any file or separately any Music File from any Browser on PC over Wifi. 

If Streaming is your goal, I suggest running a HTTP or FTP server on your android device. You can select the app that suits you from here.