[Compusmurf]

It's probably NOT a leak with the LCD screen. It's probably trapped humidity between one of the layers of the screen. it's made like a sandwich. Protective layer, digitizer layer, protective layer, glass sandwich with the LCD goop.

When your backlight (which generates a small amt of heat) warms up the ambient air inside the device, esp for folks who live in northern climates where it's cool out, that slight moisture has to go somewhere. It's usually NOT enough moisture to affect or damage electronics but it does play hell with layered screens and such.