Hi all
if you're using the last version of FireFox (3.6 or 3.5) you can listen directly to the microphones from the Icecast server page, by clicking on the loudspeaker icons : http://locus.creacast.com:9001/. In fact, FireFox supports now audio/ogg MIME type (ogg theora and ogg vorbis) without external plug-ins or third-party app. Another alternative is to open one window for each stream if you desire (ctrl +click on the ldspk icon - on osX). Very useful
best jerome