My niece has a curve, and it has a red infinity sign, like the voicemail sign, but not the same thing - with a number that keeps going up (it's up to 28 now) and we can't figure out what it is. It's not the voice mail, because she has that too, right next to it when she has voicemail. I've looked in the messages, and she has nothing pending.
ETA: She has Verizon