Audio stream from one embedded to another embedded systems

Hi, can anyone suggest the decent solution (yet affordable price) on the MCU to be used for say, a microphone is attached to one embedded system and the audio from it is stream to another embedded with an audio output, thus can be connected to an audio equipment at that end.

Any circuit diagram to any development kit is highly appreciated.

Is there any ethernet library specifically available for such task or use say Lwip stacks and I have to mingle around with it?