Apple's next iPhone won't be until late 2016, but should come with a new design.
U.S. Apple Retail Store iPhone 3GS Supplies Begin to Tighten
Apple's retail store stock levels declined over the course of the weekend, and the availability database is now showing significant iPhone 3GS shortages. According to the database, only about 40-45% of Apple's retail stores currently maintain stock of all four models, while nearly 15% of stores are completely sold out. Three states are currently listed as being entirely out of stock of all four models: Alabama (two stores), Oregon (three stores), and Utah (one store).