Existing iPhone customers are eligible for an upgrade between today and the end of this year to get the subsidized price.
In the U.S., the iPhone 4 will be available in black and white on June 24 through Apple and AT&T retail and online stores as well as Best Buy and Walmart stores. More countries will get the device on July 18 and August 24, with 88 countries selling it by September in what Apple CEO Steve Jobs called the fastest rollout of an iPhone ever.
The device is promoted as the thinnest smartphone on the market at 9.9 mm in depth, or 24 percent thinner than its predecessor, while expanding talk time by up to 40 percent to 7 hours, standby time to 300 hours, 3G Web browsing to six hours, and Wi-Fi Web browsing to 10 hours.
Other new features include a new "retina" display that boosts resolution four times to 960 by 640 pixels on the phone's 3.5-inch in-plane switching touchscreen, delivering resolution of 326 pixels per inch. At that resolution, the human eye can't make out individual pixels at a normal viewing distance, thus making text, photos and video look more realistic, the company said. Combined with 800:1 contrast ratio, Apple CEO Steve Jobs said at Apple's developers' conference here, the iPhone 4 "sets the standard for displays for the next several years."
Other new features include Wi-Fi 802.11n, Apple's A4 processor to boost performance and battery life, HD video recording at 720p/30fps, front-facing video camera for use with the new Face Time video chat capability, and a gyroscope with accelerometer that provides six-axis motion sensing for gaming. The back-facing camera goes to 5 megapixels from 3 megapixels but without making the pixels smaller than the 3G S's 1.75-micron pixels, thus not compromising low-light image and video capture, Jobs said.
Other new features include iBook reader capability, ability to read PDFs, a second microphone to reduce background noise and 3G HSUPA to accelerate uploading to a theoretical 5.8Mbps, joining 7.2Mbps 3G HSDPA downloading.
Apple's new OS, renamed iOS 4 from OS 4, adds such new features as multitasking for third-party apps, a unified email in-box, email organized by threads, ability to choose wallpapers, and mobile ads that will appear within an open app.
For enterprises, the iPhone OS 4 adds such features as the ability to wirelessly distribute apps developed in-house and encryption to protect email messages and attachments stored on the iPhone.
Other new iOS 4 features for both the iPhone and iPod Touch include online social gaming with leader boards, the ability to open e-mail attachments via third-party apps, ability to organize and view more than 2,000 app icons compared to 180, and iBook application to read e-books downloaded from Apple's iBook store. The new OS will also support Bluetooth keyboards.
The iOS 4 software will be available on June 21 as a free software update via iTunes 9.2 or later for current iPhone 3G and 3GS users and users of the second- and third-generation iPod Touch.