Pink Zombie Studios today release Door Bells 2.0 for the iPhone. DoorBells is a new door bell for the electronic age. DoorBells can be used to alert the people you visit that you’re outside their door. It allows a person to quickly call a preset contact or text them to let them know they should open the door. The default doorbell can be set to any contact, and an unlimited number of doorbells can be set up from your iPhone contact list.