I am thinking out of the box when you say, "use it as a phone."
Have you tried apps like Skype or google talk to have real time conversations with people, especially those without iPads/apple related devices.
With those that do have iPad2, iPhones or iPod's with version iOS 5--you can iMessage or FaceTime each other.
That's what I can come up with to have conversations with people.
Perhaps others may have other ideas. Good luck!