I need to install a web radio for a very small church.
For that I need to know the best software for this project.

This radio need to run random musics 24/7, but also has to have a intervention feature to allow operators to speech, sing and other things.

I know Airtime, Shoutcast and Icecast, Steamcast work for this purpose.
What I don’t understand well is the dependency between them.
For example, Airtime is built based on Icecast. This makes Icecast the core and Airtime the administration panel?
Other example: after installing Shoutcast I use Winamp to connect to it and play songs; again, is Shoutcast the core and winamp the bridge to send musics to be broadcasted?
If so, what is the best combination of softwares to use?
Show me examples, please.