AutoDJ allows you to keep your broadcasts live in the 24/7 mode without using your PC as a source (e.g. Winamp or RadioBOSS). You can upload your files and they will be played back from the server, so you can turn your PC off and your content will still available to listeners.
Follow this instructions to set up AutoDJ.
The Centova control panel allows you to control crossfades for AutoDJ. Crossfades are smooth transitions between tracks. Crossfades can be configued in Settings -> AutoDJ tab: