There are a lot of ways to approach this.
Camera
Computer
Software to do live encoding
This could be as simple as the free Adobe Flash Media Encoder (FME)
Or the free Procaster (if you're using Livestream - see below)
A software production switcher - see Telestream Wirecast forum here on the COW
http://forums.creativecow.net/telestreamwirecast
A broadband internet connection. Ideally an upload speed of about 768kbps or higher but even 500kbps would be OK. The connection to the computer can be wifi or ethernet (wired).
In order to provide more direction you'd need to provide more details but the above can get you going.
A service to accept and distribute the stream
Livestream
or
Ustream
Both have Pro accounts if you don't like the ads. Both allow embedding in your own web page.
