Yes, it's called LCD screen image persistence. The Good news appears to be that unlike plasma screen and phosphor screen burn-in, persistence is generally reversible.
It's caused by the the liquid crystals that are in a turned on state for very long periods of time not "relaxing" completely back to the non-activated state. There's two main approaches to reversing the problem:
Turn the screen off and do not use it for an extended period of time. This may vary from a few days to a few weeks, depending on the nature of the liquid crystals and how bad the problem is.
Set up a screen saver that is one white image that covers the entire screen. Set the screen saver to activate in a short amount of time, say one or two minutes. Set the screen to turn off after about 15 minutes of inactivity. This way, when the computer is idle it will display the white screen for less than 15 minutes, then go blank. After a period of this you should see the problem lessen and eventually go away. When the problem is fixed you can go back to a normal screen saver, or simply do as I do and set the screen to turn off after a reasonable amount of time.
The last solution (2) is one that seems to be suggested a lot, however I believe that the first solution is most likely to reverse the problem completely and in the shortest possible time.