Streaming music between several devices

ATV units will allow you to do this pretty cheaply...I think the new ( ATV3) ins under £100.00 UK further information:

http://www.amazon.co.uk/New-Apple-TV-Latest-Model/dp/B0040GIZT8


If you want a slightly cheaper option, Roku also make a similar device:


http://www.amazon.co.uk/Roku-XS-108...2?s=electronics&ie=UTF8&qid=1362729043&sr=1-2


Can't vouch for the Roku, but a search here should help you choose.

 

I assume you mean some sort of iOS device (iPod, iPad, iPhone) then you would need to write the audio streaming code yourself. Typically you would need some way to connect the devices. If its a one to one you could use bluetooth to pass the data back and fourth. If its multiple devices. you would need to create an app that is a client server based app where your source becomes the server and the other devices connect to receive the data over sockets. This is a trivial thing to do on a wifi connection but when you start trying to do it ad hoc you have to start creating your devices as a mobile hotspot. This can be done and there are samples. However the default hotspot works as socks proxies and does not allow for simple bonjour connectivity.