You need:
• An input (This could be a file or a firewire DV camera)
• If live: a way to accept the signal from the firewire device (dvgrab)
• A way to convert the firewire input / the file to a format that is acceptable for the streaming server (ffmpeg2theora)
• A way to send the file to the server (oggfwd)
• Access to a streaming server (Icecast - you can use giss.tv for this)

giss.tv
developed by Yves Degoyon
password host.ogg is:
t7vjr
The user to broadcast to giss is 'source'
The server to use to broadcast to giss is 'giss.tv'
The port to use to broadcast to giss is '8000'
The address to see/hear your stream will be
http://giss.tv:8000/host.ogg∞

STREAM FILE
cat /home/fsnelting/Desktop/mobiel.ogg - | oggfwd giss.tv 8000 t7vjr /host.ogg

STREAM LIVE
dvgrab --format raw - | ffmpeg2theora -a 0 -v 5 -f dv -x 320 -y 240 -o /dev/stdout - | oggfwd giss.tv 8000 t7vjr /host.ogg

SAVE STREAM
mplayer -dumpstream "http://icecast.v2.nl:8000/livingroom∞" -dumpfile host.ogg
(or replace by any other public broadcast address)

Components

cat
Concatenate files(s), or standard input, to standard output.

ffmpeg2theora
ffmpeg2theora is a program that converts any media file that ffmpeg can decode to Ogg Theora for video and Ogg Vorbis for audio.
• -o output (in this case: send to /dev/stdout can be a name for the file, a place to save it)
• -a audioquality [-2 to 10]
• -v [0 to 10] Set encoding quality for video (default: 5)
• -f format
• -x / -y width + height
• --aspect 4:3 or 16:9 or...
• --croptop, --cropbottom, --cropleft, --cropright
• -f input format
• metadata: --artist --title --date --location --organization --copyright --license

dvgrab
Capture DV or MPEG-2 Transport Stream (HDV) video and audio data from FireWire
- = standard-in

oggfwd
a minimal source client for Icecast servers. It reads an Ogg stream from stdin and forwards it to a server specified on the command line.

mplayer
mplayer is a movie player for Linux (see also mencoder)