We've created an online radio application that allows you to be a DJ to your own online radio station powered by the iPhone, Flash and Flash Media Server. Start by uploading MP3 files to your server via either your own FTP or if you have the required software and availability to certain settings on FMS, then do it right within Todja!
Once those are in you can set up the files into a playlist and have it run until you tell it to stop or loop forever. With that of course you can broadcast yourself live, adjust volume for both mic and song and check out how many people are listening to your radio channel all from within one interface.
This iPhone application is solely for the purpose of listening to the music, the rest of the application is an online purchase outside of the app store due to it's complex build and required user interface.