I am a Windows user and i recently bought a server to Broadcast live on the Internet at around 300-350 kpbs, I know its a Broad question but What kind of software should i use on my linux based desktop which i am turning into a Server to Broadcast online. I am looking at around 50 users eventually and i would want to give unique mms/http links to every person, the links i would not want to be used by more then one user at a time.I can also give the ip address of my server and have password authentication for the users.
Recently I have been streaming using Vlc player and it Works flawlessly but in Vlc player, I give the ip of the computer i am broadcasting from to the users and they just access the steam. One of the other solutions i was told about was to get windows 2003 enterprise and use media server. Currently i have an Internet connection with speeds of 6 meg and upstreams of around 800 kpbs.
Another thing i have not been able to fathom, for the past few days i have been broadcasting at around 300-350 kpbs, now if i have a 6 meg connection does that mean that i wont be able to stream to more then 15 users? I tried Vlc player with more then 10 people and it seemed that i could get a lot more users.

Well, it's just the upload speed you should be watching after. The stream flow is directed from your machine towards the users, which is upload. And by the time your ISP gives you 800kbps, you're capped. But in fact that's not the case, vlc just like other streamers has buffers and transport optimizers which might push a bit more out of the crappy connection and yet some ISP's tend to measure and shape their upload traffic much less precise than others. Try to measure the actual traffic flow with iftop(f.e.) and output results.