Come on, now. Everyone thinks they can hang a new LCD or plasma television. I'm reminded about what Mike Tyson said about boxing, "Everyone has a plan 'till they get punched in the mouth."
I've seen a $1,899 LCD television, face down, on a wood floor after it fell from the mount and it wasn't pretty. Here in the Seattle area you can spend around $375 to call in contractor to hang a wall mount and large screen TV. Basic guaranteed service includes the mount installation, TV set-up, and plugging in additional components (VCR, Blu-Ray, and satellite or cable box). You'll pay more to have a new wall box, wall plates, a new electrical outlet behind the TV, or in installing full-motion mounts.
Or, you can do it yourself
Relax; it's a minor home improvement effort. It's not like you'll be building a home recording studio. The most-critical step in it all is finding the mount that easily supports the full weight of your new TV.
The tag of the mount may insist it hangs up to a certain diagonally-sized television. Or the teen clerk with acne at the big box store might take a break from his headphones to tell you it's a gimme. Ask to speak with the department head of the store and ask him to show you a mount designed exactly to hold your model. Some manufacturers pair up their models with their own mounts.
Next, make sure you have the right hardware and tools. Over at This Old House, Tom Silva insists on using toggle bolts if you're doing steel frame hanging. Use the mount's template to drill your holes and use the largest bolts that fit into the diameter of holes in the frame.
Popular Mechanics recommends that you find studs rather than expecting hollow-wall anchors to handle the job. Put your new TV face down on soft carpeting and attach the connecting mount pieces to the rear. Once the wall-side of the frame is secure, you can heft the TV to its place.
The best place to hang your new set is just above eye level in a location that serves the key sitting area of your room. If you're running any cables through the wall, be sure to drill holes behind the mounting location - and run them through before mounting the TV. Check for placement where it won't pick up glare from a window or frequently used lamp. Perhaps the best alignment won't face all your seating directly. C'est la vie.
If you're not using any kind of swivel system, be sure you adjust for level before torquing down the wall screws.
And that's it!