"Yesterday, Mobile Orchard’s own Dan Grigsby posted about how he performed Apple-approved iPhone interprocess communication using URL handlers in his Alocola iPhone app. Shortly thereafter, Ryan Johnson of InnerFence commented that they’ve been doing the same for a while with their own apps. InnerFence are perhaps best known for their powerful Credit Card Terminal app that enables you to turn your iPhone into a credit card terminal for taking payments on the fly. They’ve used two way app communication (via URL handlers) to allow other apps to use the Credit Card Terminal app for processing payments (jn particular, Ring It Up)." - Graham Sergeant