Apple has posted a support article that concerns MagSafe power adapters:
You may notice a separation of the white insulation on the magnetic end of the MagSafe adapter. Under continued use, the cable may discolor and the rubber molding may become deformed. Products affected: MacBook (13-inch Late 2006), MacBook (13-inch), MacBook Pro (15-inch Glossy), MacBook Pro (17-inch)
Whether your product is in or out-of-warranty, you can take your adapter (you don’t need to take the computer) to an Apple-Authorized Service Provider or Apple Retail Store for evaluation, and replacement if necessary. You may be eligible for a replacement adapter free of charge provided there are no signs of abuse. Make a reservation at the Genius Bar before visiting your local Apple Retail Store. To make a reservation, go to http://www.apple.com/retail/geniusbar/
Apple’s support article is here.
[Attribution: MacNN. Thanks to MacDailyNews Reader “Fred Mertz” for the heads up.]