wireless camera system

hi i want to present a basic wireless system using few camera, bridge, routers and monitor so as to set up a wireless security system. i would really appreciate if someone could give me some advice of how to do this system... at first i wanted to set it up using RF in GHz range to avoid interference. Can anyone advice me please.
thanking you in advance.

Just buy wireless IP security cameras.

Or you could use webcams with mjpeg capacity, low powered PCs (i.e Acer Revo or similar) running Linux and mjpg-streamer and a program such as Motion for Linux to capture / detect motion

The downside of webcams is that they don't tend to be very useful when it gets dark.