I work at a webcasting company. We stream live video events from around the world.
Hardlines Webcasting
Typically, the software makes everything fairly simple. The events we produce have a large number of concurrent viewers, so we use Akamai for providing the bandwidth.
Basically, the software itself is the "server", so you'll have to punch a hole in your firewall, etc.. You set up your camera, connect it to your computer, configure your video settings (bitrate, resolution, etc), and hit publish. Users can then connect to your computer to watch the stream.
With Akamai, it's basically the same, but instead of the users connecting to your machine, Akamai's servers connect to get the stream, then they redistribute it to the end users. There is a fair bit of configuring to do to initiate a new stream through them.
If you are interested in hiring someone to produce a webcast event, please consider us. We are very experienced, and have resonable rates.