Analogue (audio) / Ethernet interface

Bonjour,

Discovering Arduino, I would request assistance to explore the possibilities to design Analogue / Ethernet interface (to/from) for analogue signals ranging 1000 - 30000 Hz.

Friendly,

What Arduino would you use?
It is not the sort of thing you could do with a Uno.
Ethernet implies voice over IP protocol which is not easy to implement.
What is on the receiving end? Does it know about voice over IP protocol?