Starting the other day, a new icon appears in the upper left corner of the clock/screensaver on the miniscreen. It looks like a phone handset with an arrow pointing at it from the left. It also appears in the clock screensaver on the main screen if the phone is left open.
I have no idea what it means or how to get rid of it. I've tried resetting the phone, deleted all messages, removed all call forwarding, no dice.
That icon means there is a new missed call in the missed call list. If you missed a call sometime and pressed "exit" instead of "view" when you opened your phone, then it is still listed as a missed call. Go into the call log and go to missed calls, and your new missed calls should have a number under them of how many times they were missed.
This confused me too at first, but then I figured it out.