The iPhone is a sleek, delightful device. For the most part, I love its profile. Trying to squeeze it under my chin durin a call while scrambling for a piece of paper and pencil, or performing some other task, becomes problematic. I inevitably end up putting the person on hold or even cutting off the caller entirely. Thanks to a new tweak available through the Cydia store, the errant hang-up is a thing of the past. CallLock is an app that runs in the background and allows the user to manually or automatically have the screen lock during calls. When a call comes through, you merely tap the Power button and the screen locks without ending the call. You can toggle to the automatic mode through the Settings app, so no new icon is added to your home screen. The app is 99 cents and requires iOS 4.0 or later.