Your local supplier should be able to price materials. Home depot has this stuff also. Figure out what materials you need then price labor the same as you would for running any other type of wire. Maybe add a little more profit. The networking companies are not shy about charging top dollar for this kind of work which is really quite easy.
I agree with Scott and would like to add that the Pass and Seymore system IMO is a much better quality than the Leviton system that HD carries. The P&S system is very flexible, is always expandable, and their tech support is top notch.
You could do phone, tv, networking, home theatre, video cameras, etc... It is also possible to incorperate X-10 cameras and components into the system to work via internet access.
open an account at a tel/data supplier and/or a security alarm supplier. the electrical distributors are generally not well-versed in home theater/security/cctv/catv/soho network/etc. security distribution does a lot of small office/home office supply.