Here you can find PicoStreamer, a set of script to build your own Internet station.
Starting from the v.2.2 you can broadcast live video usign Flash embedded source and player: internet broadcasting has never been so simple!
Main difference between PicoStreamer and other streaming software, is that you don't need to use a dedicated machine: a classic hosting space with Perl/PHP is enough to setup a true real LIVE web station.
Download it, check online documentation and, if in trouble, get help on forum.
This site tracks PicoStreamer stations in a directory listing so, if you don't want setup your own web radio, you can ever enjoy listening channels. Remember: PicoStreamer stations can be listened over business firewall and proxies; if you can browse the web, than you can listen.