Radiodan is Open Source software that lets you build your own internet radio on a Raspberry Pi or in pure software.
We've built it using some BBC radio streams, but it is easy to use with other streams, and to add MP3 files (and other audio formats). We're busy building the new version with NodeJS, RabbitMQ and MPD. It can run on most UNIX-based operating systems, with particular emphasis on Raspbian.
We've made it because we are interested in different kinds of physical radio devices and how we might change their functionality to make them better. We think that it's only possible to test what makes a radio better by building devices that act like radios, and that the more people who can build them, the more interesting the radios will be. If you like videos you can see our nextrad.io presentation (9 minute video) which explains more about what we are trying to do.
Radiodan and Radiodan Example app are alpha-quality software, but we've released a version 1 while we work on version 2, and if you'd like to have a play, the instructions are here (but do get in touch, we are happy to help, and you may need it!).