In case you have no friends, or just no friends with an iPhone 4, you can call Apple to test out the new FaceTime feature. All you have to do is call 1-888-FACETIME (188832238463) from your iPhone 4 and you will be connected with an Apple representative. They will then briefly explain the features of FacTtime to you and a few tips and tricks on using it. Don't try any of those late-night tricks though, the help line is only available from 8AM to 8PM CDT.
