If you are using WinAmp, Station Playlist, etc. to broadcast, you will need external encoders to connect to your stream. Most people have been using the WinAmp dll as a plug in.
Believe it or not, the WinAmp.dll used as a broadcast plug-in for WinAmp crashes. This is totally funny, as both SHOUTcast and WinAmp are AOL / Nulsoft products.
It crashes for a fact in Windows 7. Some people have had luck with Windows XP.
The workaround is to use the EddCast plugin for WinAmp (or whatever software you use). The good news is it doesn't crash. The bad news is it is not set up for SHOUTcast 2 and can only handle the 1st mountpoint.
Here is a link to download it: http://djlab.com/stuff/dj/edcast_standalone_3.1.21.exe