According to one of the most reliable sources of Apple rumors, the upcoming iPhone model — maybe called iPhone 5 — may have a 4-inch screen.
Jeremy Horowitz of iLounge is saying that the yet-to-be-announced model will have a “10mm jump in height, (and) nearly 2mm reduction in thickness”.
All current iPhone models, including the latest iPhone 4S, sport a 3.5-inch screen made from hardened glass. The first-generation iPhone used a special kind of hardened glass called Gorilla Glass (manufactured by Corning Inc), while other generations probably used another type of aluminosilicate glass.
The new iPhone will use Gorilla Glass 2, according to iLounge. It will also have a narrower dock connector with fewer pins than the current 30-pin one.