1. develop very-low-cost hardware capable of receiving a network (TCP) stream and play it. The hardware consists of an arduino controller board, an ethernet shield that had to be slightly modified to work with the mp3 shield (see previous posts describing the connections of these components). Final arduino software is available here (note limit to the playback of 32 kbps bitrate maximum on the hardware client app).
2. develop a windows application written in Delphi that:
a) automatically adds speaker clients as they are added to the network
b) manages the speaker database (allows grouping of speakers, edit names and descriptions, delete and manual add).
c) sends only one stream to the network (to decrease bandwidth usage) but selects speakers or groups of speakers for stream playback.
3. Develop a windows client application that emulates the arduino hardware (in this implementation, this is NOT a general arduino emulator!)
The software described in 2. and 3. can be used without any HW client to stream audio (mp3) content over the network from a server to a client.
All software is available here (the latest versions are the top three on the list for each of the described components).