Can anyone tell me what I can do to host BYOND games on my system?
I need to know:
1. Any special software other than BYOND Dream Deamon?

I'd recommend some sort of decent firewall software that prevents any incoming requests from ports other than the port you've used for hosting in Dream Daemon.

2. CPU usage?

Depends on the size of the game. A game of reasonable size (say, a MUD oriented for up to 50 players) should work on a middle-road 466 MHz processor, assuming you're not performing thousands of calculations. A massive multiplayer MUD would need a high-power multi-GHz processor. A tiny chat could be run from a 100 MHz or less.

Naturally, you would need to have a high-speed connection to host anything with a decent speed, however. Chats can be run from 56K's, reasonable-sized MUDs can be run from cable or DSL easily, and full-fledged massive multiplayer MUDs would probably need a hardcore T1 fiber-optic line.

3. Possible with Win NT?

Not sure, but I don't think so.

4. Bugs issues?
5. Security issues?

None that I know of, but you can never be too careful. Run in safe-mode hosting.