Home Surveillance System

[Snicla]

So I'm thinking of placing cameras around my house, what are the things that I should be considering if I want to do this myself? What kind of materials would I need? Equipment and places where I can get this equipment for cheap. Ideally I would want to have 4 cameras, all of which will be on the outside, hooked up to my TV so that I can monitor things from my living room. I want to be able to monitor all 4 cameras simultaneously.
Thanks :)

[g0lden0rchard]

Motorola made some good products called HOMESIGHT.

I think the line was dropped but you might be able to find it for a good price somewhere