CCTV and cheap do not belong in same sentence, alas.....do you want pan-tilt-zoom control over said camera?
edit: There is web site that has stuff SOMEwhat similar to what security companies install, and prices aren't bad
supercircuits .... If you want long-term hard drive storage of said video, you will want a dvr (which has network interface, thru which you could control said cameras(s)...they have software/firmware that can cram weeks of video onto a 600 gig hard drive.... lotsa stuff to consider
(oops) Is said camera(s) indoors or outdoors?