Apparently one of the newer characters on Heroes can "see" certain sounds as colors. (I gave up on the show last year, so I'm a little behind.) Of course, she can also convert those sounds into concussive energy blasts. Of course. I will refrain from calling her "Deaf Dazzler:"
The medical term for this is sound-color synesthesia, and the condition has also been featured on House.
It's pretty freaky to think about what it would be like to live in a world where everything you heard was instead redirected to your sight. I'm sure that, in reality, it wouldn't be as clean as visible-spectrum colors mapping linearly from audio frequencies, but I'm a lazy writer.
Read "Within Sight" at 512 Words or Fewer