Noob question starting streaming service

[demon]

Hello

i am new here so i would like to apologize for some noob questions i am about to ask but i would really appreciate if someone could help me answer them.
I would like to start a streaming server to provide some of my clients with streamin video solution.

1. what are internet channel Bandwidth requirements for the server ( Streaming MPEG-2 to 200 - 500 clients)?
2. Equipment requirements for streaming server ( Currently have quad core xeon with 6 gb ram and 4x750 GB Sata II supermicro server with FreeBSD 7)
3. Content ( I would like to purchase content eg channels package from some company ) where should i start looking?
4. Set top Box . what are most price / quality Set top Box for Playing Content from streaming server (currently found solution from http://peertv.com/ )

if some one has experience with building streaming server would really appreciate any tips and comments

Kind Regards
Demon