I wouldent advise you do that... things like shoutcast and jetcast are not suitible for streaming audia/video to people you dont know because they are basically connecting DIRECTLY to your computer/hard drive using those kinds of software. (and it gets around ur firewall if you have given that program access rights to the internet.)
Also, software like that is limited to ur internet (upload) bandwidth. if u have some audio at 20Kbps (20Kbps is fairly low quality) and you have an upload speed for 33k (like on a 56K modem) then you can only have 1 person listening to ur radio. (You can calculate this by taking the upload bandwidth divided by the bit rate of the audio)
If you want more people to be able to listen to ur online radio then get a server (they are quite expensive, if you dont have the funds then find a friend who does and ask if they can upload it to their server for you.
Or you can try a free or evaluation server here.