During his keynote address at the Worldwide Developers Conference (WWDC), Apple CEO Steve Jobs unveiled his company's next smartphone, the iPhone 4. Billed in typically hyperbolic fashion as "the thinnest smartphone ever," the iPhone 4 will enter an increasingly competitive market, with the iPhone in danger of falling behind to Google's more diverse Android system. So instead of sharing the limelight with other Apple products or technologies, the iPhone 4 was the only topic that Jobs discussed during his address.

While the iPhone 4 comes with a number of new or improved features, two stand out. The device features a video call feature named FaceTime, though it works only over Wi-Fi and only between two iPhone 4s. And the iPhone 4's screen, while no larger than that of previous iPhones, now comes packed with four times the resolution, at 960 x 640. It's dubbed the Retina display by Apple because it packs 326 pixels per inch, more than the human retina can even see.

"iPhone 4 is the biggest leap since the original iPhone," Jobs said in a prepared statement. "FaceTime video calling sets a new standard for mobile communication, and our new Retina display is the highest resolution display ever in a phone, with text looking like it does on a fine printed page. We have been dreaming about both of these breakthroughs for decades."

The new iPhone 4 is made of glass, front and back, with a stainless steel band around the edge that reinforces the device's rigidity and amplifies the antennae. Answering complaints from previous iPhones, the iPhone 4 finally packs a decent camera, offering 5 megapixels, 5x digital zoom, HD video recording, and, finally, an LED flash. A second camera on the front works with FaceTime for video conferencing. Apple will provide on-device movie editing via a new iMovie for iPhone app, though it will cost $5 and does not come with the phone.

Apple will deliver the iPhone 4 in a much more timely fashion than previous iPhones. Customers will be able to preorder the device in the US starting June 15, and AT&T customers with contracts expiring anytime in 2010 will qualify for upgrade pricing at that time. A 16 GB iPhone 4 will cost $199, while a 32 GB version is $299 (upgrade pricing). The units are available in white and black.

Apple will also deliver its new iPhone OS 4, renamed to iOS 4 because it works across different products, on June 21, for free to all customers with compatible devices. These include the iPhone (all models but the original), the iPod touch (all models but the original), and, later this year, the iPad. Note that some iOS features require newer devices, such as multitasking support.

Later in the day, and unrelated to the keynote, Apple quietly shipped an update to its web browser for Windows and Mac, Safari 5. This browser looks and works much like its predecessor and offers a number of updates around HTML 5 compatibility, performance, and extensibility. There's also a new Safari Reader feature that makes reading online articles less cluttered, and Bing integration, so that users can switch to Microsoft's search engine if desired. Bing will also be an option in the version of Safari delivered with the iPhone 4 and iOS 4, Apple said.