this number occasionally shows up when the other caller is calling using Skype. (http://www.skype.com for info on Skype). I noticed this myself when I used my own account to call my landline.
another number that may show up from a user of this VOIP service is (000)123-4567.
It's a VOIP service number from VBUZZER. It's a great service, 5 dollars for 500 minutes or 10 for 1000. Take advantage of your unlimited incoming wireless service.