Dr. Macenstein suggests that now is the time to act. He writes (and he is a he, right--it's not a Frau Doctor Macenstein?) that Apple Store Genius say there's currently no official stuck pixel policy for iPhones (while there are official policies in place for monitors and laptops). If your iPhone suffers from a bad pixel or two, you'll want to bring yours in and get a replacement asap, i.e. before an official policy rears its ugly head. The article tells you how to check your iPhone for pixel problems by adjusting your iPhone display brightness.