When Apple announced the iPhone at WWDC, Steve Jobs said that the iPhone 4 will be available for pre-order starting on June 15th and on sale on June 24th. Users interested in the Cupertino-designed smartphone can order through Apple and local carrier partners, including AT&T in the US. The device will initially be launched in 5 countries and will progressively be made available to many more countries in the progressing summer months. Another source for iPhone 4 purchases if you don’t want to pre-order would be local Best Buy stores, which is said to have a minimum of 45 iPhone 4 devices per store according to Engadget: “A minimum of 30 units for the 32GB device and 15 of the 16GB will apparently be available at each store, and employee purchases are banned at launch.”
Another source to acquire your iPhone 4 with its stainless steel frame and glass front and back panels would be Radio Shack, though it’s unclear how much inventory there may be at Radio Shack.