Originally Posted by sempai
You have a voicemail.
That's not exactly correct. The reel-to-reel (eyeglasses-looking) icon is the indicator that there's a message. The phone icon means that you missed a call. This also means that you've elected to see phone log information in your messages list, and that you need to clear the call (mark the phone message as 'read').
You can clear the call by either opening the call message, or just selecting it from the message list and doing alt+u.