How do you use facetime on the iphone 4s without service, but with wifi?
You can use Facetime on the iPhone 4s with WiFi once you not cellular service. You need to login to Facetime account and get connected to your friend who is on Facetime. See more details at http://www.ilounge.com/index.php/articles/comments/the-complete-guide-to-facetime-set-up-use-and-troubleshooting-problems/.
You have to FaceTime someone else who has FaceTime. You both have to be on wifi to use it.