I did this and started by asking myself some questions:
1. How big of a TV did I want.
2. Do I need it to:
Move at all, pivot, or hide away?
Here is a similar set-up to mine:
http://www.irv2.com/forums/f121/outlaw-mods-and-easy-fixes-149108.html#post1440361
Please notice that (for the kids) having the TV across from the couch is better than over the drivers head.
The options in Q #2 are listed in order of expense...
~Mounting the TV on the wall is cheapest and easiest. Just build a box and you are done.
~Mounting the TV on a full motion mount is easy, just gets more costly for the mount, but they are affordable.
Like this:
Cheetah Mounts Swivel Articulating Arm TV Wall Mount (23'' - 32'' Screens): TV & Video : Walmart.com
or ceiling mount, Like this:
peerless Ceiling Mount w/ Cable Management for 13-29 LCDs : Ceiling Mounts | RadioShack.com
~Hide-away is CRAZY expensive.
See:
Flip Down Ceiling Mount ceiling for 40-50" TV- anyone try to DIY?
I went with the articulated arm (full motion) mount.
Best of luck