Although this address the same issue on the 17" model, it may solve your problem.
Apple has issued a firmware update for its new 17-inch MacBook Pro which, supposedly, addresses a problem of vertical lines appearing on the display. The problem is apparently being experienced by a portion of owners of Apple’s new 17-inch unibody MacBook Pros: some displays show green vertical lines and other display anomalies when using the integrated Nvidia 9600GT discrete graphics processor.
Apple’s svelte (770K) update appears to fix the problem; however, it is not the first time Apple has had issued with the Nvidia graphics controllers used in its MacBook Pro systems. Some users reported the vertical lines problem only happened when the laptop was running hot; others reported the problem even when the 17-inch system was running cool.
Owners can download the firmware update from Apple directly, or pick it up automatically via Mac OS X’s built-in Software Update feature.
If this fails the problem is most likely with the inverter cable. I would check the connections. This is Apples part number 922-8713. I don't see where iFixit carries it but there are several links. Do a search for Mac & 922-8713.