It's all about shutter and white balancing. I've been doing these kinds of photos for a while now.
I also sometimes even purposely de-focus the camera a little to prevent a moire effect.
http://img.photobucket.com/albums/v3...n/IMG_0515.jpg
http://img.photobucket.com/albums/v3...n/colors-1.jpg
http://img.photobucket.com/albums/v3...n/_IGP6830.jpg
Basically when I am white balancing, I white balance to a greyscale pattern on the TV.
For shutter speeds, I generally shoot for 1/30th shutter, because that will get both fields of an interlaced display and help make it look like a more complete picture. If you do a 1/60th shutter, you get only 1 field captured.. Any higher and you have an incomplete picture now, not even a full field, black bands, etc..
For aperture, I tinker with that depending on how bright the TV is. But remember, the lower the aperture, the more light, BUT, the more "soft" it may get.