Could be useful for meetings or events.

http://ffmpeg.org/trac/ffmpeg/wiki/Streaming%20media%20with%20ffserver

Stream audio only:
{{{
Port 8090
BindAddress 0.0.0.0
MaxHTTPConnections 2000
MaxClients 1000
MaxBandwidth 1000
CustomLog -
NoDaemon
<Feed feed1.ffm>
File /tmp/feed1.ffm
FileMaxSize 5M
ACL allow 127.0.0.1
ACL allow <your ip>
</Feed>
<Stream test.mp3>
Feed feed1.ffm
Format mp2
AudioBitRate 64
AudioChannels 1
AudioSampleRate 44100
NoVideo
</Stream>
<Stream stat.html>
Format status
ACL allow localhost
ACL allow 192.168.0.0 192.168.255.255
</Stream>
}}}

Client to stream from microphone:

{{{
ffmpeg -f oss -i /dev/dsp http://personaltelco.net:8090/feed1.ffm
}}}