There's no question the panel is 120Hz. The refresh rate is all hardware and cannot be adjusted by a software update.
TruMotion (in short) is simply a software algorithm which attempts to smooth the picture. It can be very effective at removing motion blur. Many viewers enjoy this feature on a low setting. TruMotion does smooth the picture when the camera pans or fast moving objects are on-screen with minimal 'noticeable' downsides. The feature can introduce unwanted artifacts or an effect called Soap Opera Effect (SOE) when cranked up high. Some people really enjoy the SOE however, so that’s not necessarily a negative experience to all viewers utilizing motion compensation. SOE is a matter of preference but there will be 'noticible' artifacts here and there.
Hope this brief description makes it a little clearer.
Edited by Brecklington - 6/8/12 at 4:57pm