I have been given the task of coming up with a way we can do a webcast from our server, here is the setup we need.

One windows computer with a mic that can take the audio and stream it through a linux server to up to 100 users on the web, also a chat that anyone in the webcast can type questions and then can be answered through the audio. So that being said the audio has to be realtime.

And of course it has to be realitively cheap, software for 100 to 200 dollars is fine, but I can't buy the 2,000 dollar server from real.com

Anyone that has done this before that might be able to lead me in the right direction would really be appriciated.