Yes, current LCD TV can be used as a computer monitor, by connecting to your CPU or notebook directly via a VGA cable.
However, is it really workable and able to replace your REAL computer LCD monitor?
Not really. When I connect my Dell D800 to my Sony 40″ LCD, the highest resolution that it can support is only 1024 x 768px, which is pretty low and not the highest resolution my D800 can deliver (1280x 800). The screen size also does not go full to the Sony TV.
Refresh rate wise, not really sure but I can see lines flicker around the TV. I supposed it might be less than 60Hz.
So, my simple conclusion is…you can connect your LCD TV to your computer, but it can’t replace your computer LCD monitor or exisiting monitor on your notebook. It is good to watch movie, simple internet accesss, relax work, but definitely not for the serious work.