I use SVAT product line. The systems start from 4 cameras and go up to 16. The DVR has a built in server that is user programable. I can look at my systems from anywhere in the world. And the prices aren't too bad.
to configure cctv system on the internet you need to have a dsl internet connection with a static ip address. you can connect with that ip address from anywhere and then you can access the server with DVR.