Jimbo:
There is a ton of discussions regarding this out there on google, it seems basically that your TV performs this adjustment internally by using a multiples of the source so if you have a 60hz source then your tv will basically display each frame 4 times per sec on a 240hz TV. The problem evidently comes when the conversion process is harder to sync like a 24hz source and a 60hz display.
I'm really new to this stuff myself and am currently thinking of sinking a good chunck of cash into a new TV so I've been googling the heck out of this and am currently suffering brain boil.
A couple links for you
240hz, 120hz, 60hz Effect with Cable TV - AVS Forum
and
Motion blur illustrated - AVS Forum
Are you suffering from any blur, jitter, stutter, pixel artifacts, jeez I'm suffering from utter confusion over just trying to get some information to help with a new TV purchase. Good luck to you