Question about live streaming screen capture

Hi,

at my office we conduct live video broadcasts using widows media encoder, and we're working on moving away from it to a newer method, which most likely will be something flash related.

how the procedure is done today is that a user logs in the windows media encoder program, starts the broadcast, the broadcast starts building an asf file in the server people watch, our users get the link and they join. once the broadcast is finished, the host that did the broadcast exits and saves the file, in the video server. the broadcast is a screen capture presentation of what a host has in his computer.

I want to achieve this or something similar, using a broadcast on flash streaming, so that both, users can log to a link we provide to them, the video server saves the file (preferably as .flv) and of course the broadcast is done nice and smoothly without interruptions or gaps (or at least with a minimum amount).

my question would be,

what process do you guys use to broadcast ? say other members. I'm talking about a simultanous broadcast for about 200 people, I guess it's similar to the numbers that you handle.

I'm pretty wide open on slight modifications on the process, such as maybe the host of the broadcast, saving the broadcast file in his computer and uploading it into the video server afterwards, although I would pprefer of course if it's pushed directly.

resources that I have available:

we have a windows media server -the one we're using right now, and we also have an adobe flash media server, with full license. we have a flash encoder but so far we haven't been able to figure out how to maintain a screencapture broadcast. it works, but only for about 2 minutes and then the player stops reproduction of the broadcast, however the encoding still goes on.

so, while you can answer my request, if you can talk about your broadcasting experience, on broadcasting screen capture...

I am open to all recommendations and suggestions, and I am thankful to all your responses.