If you want to provide music to a SHOUTcast server directly from the same server (instead of streaming it to the server from you PC) then SHOUTcast Transcoder is your weapon of choice.
However, out-of-the-box the SHOUTcast Transcoder supports only the playback of static playlists. If you, however, like me want to stream music from a FTP directory where the contents constantly change, you will find the rigid concept of static playlists quite unhandy. Although there are some webapps that support the server-side management of music content for the SHOUTcast transcoder (like Centova Cast), these are expensive and overkill for the above mentioned purpose.
Therefore, I wrote a script in Python that provides the mentioned functionality. Additionally, it can mix in a jingle now and then. Download the fully commented dynamicPlaylist.py script.
You can also join the discussion in the Winamp forum.