Stream ALSA to ICECAST

arecord -f S16_LE -c1 -r16000 -D RADIO - | \
lame -r -s 16 -b 16 -m m -cbr - - | \
ezstream -v -c ezstream.conf

Where "RADIO" is an alsa source as defined in ~/.asoundrc (not required but if you're doing crazy stuff like this you're probably rockin' multiple sound cards and this helps you keep your sanity)

pcm.RADIO {
       hint.description "SignaLink USB"
       type hw
           card 1
}

ezstream.conf

<ezstream>
   <url>http://your-server-url/robtest.mp3</url>
   <sourceuser>source</sourceuser>
   <sourcepassword>your-passwd</sourcepassword>
   <format>MP3</format>
   <filename>stdin</filename>
   <svrinfourl>http://your-server-url/robtest.mp3</svrinfourl>
</ezstream>

Requires

alsa-utils  Utilities for configuring and using ALSA
lame        MP3 encoding library (frontend)
ezstream    easy media streaming client over icecast servers