For Icecast streams, use the following:

Goto Edit, Preferences from the Netscape menu bar

Select Applications from the Navigator tag

Click New...

Enter Icecast Stream for the description.

Enter audio/x-mpegurl for the MIME Type.

Enter m3u for the suffix

Click Application

Enter xmms %s in the application dialog box.

For Shoutcast streams, use this:

Goto Edit, Preferences from the Netscape menu bar

Select Applications from the Navigator tag

Click New...

Enter Shoutcast Stream for the description.

Enter audio/x-scpls for the MIME Type.

Enter pls for the suffix

Click Application

Enter xmms %s in the application dialog box.

Done! Now you don't have to feel strapped to using Winamp on your Windows box to listen to all that nice music out there. While I'm at it, keep your eyes peeled for The Linux Pimp's streaming audio server which should be online in the next week or so!