Use what is known as a clock receptacle behind the TV. It is reccessed and allows the TV to be plugged in without a bulge from the plug.
Here is a picture of one from http://www.levitonhelpdesk.com/catalog/search/Clock-Receptacle-1.htm

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The LCD series use an external power supply similar to laptops. The recessed wall clock outlet is a great idea. If there is clearance behind the set with the wall mount brackets, you can hide the supply back there tied up with velcro or tywraps. If there isn't, you may want to install a full recessed box to stow the supply, outlet, and cable entry. It all depends on how handy you are.

Please tell me more about these "full recessed outlets". I'm trying to hide a cord of an electronic dart board and the clock outlets do not seem deep enough.

Thanks!

Build a small pocket back into teh wall and place a receptacle in the pocket. Place whatever equipment you need in the pocket.
Watch out for heat.

You might also want to consider a recessed outlet kit (see link below). These kits take any decora outlet (110v or low-voltage such as coax cables) and make them recessed.

They also have a cover you can use that you can drill a hole through for your cable and make a very clean look. We used them in our home theater and they look great.

Here is a link that might be useful: Recessed clock outlet kit

Heres a guide on how to wall mount your LCD/Plasma TV on the wall and hide all the cables. Its pretty good and the site also sells all the stuff you need to do it :)

Here is a link that might be useful: How to wall mount LCD/Plasma TV