During a keynote address at WWDC today, Apple CEO Steve Jobs announced the next revision of the company's iconic iPhone hardware. Dubbed "iPhone 4," Jobs called the new iPhone model "the biggest leap since the original iPhone." He said that the new device has over 100 new features, but he detailed just eight of them during his presentation.

Physically, the new iPhone resembles the prototypes that were leaked earlier by Gizmodo and Tinh t?. In particular, Jobs noted that it was 9.3mm thick, or 24 percent thinner than the iPhone 3GS. Jobs called the iPhone 4 the "thinnest smartphone ever."

As expected, it features a camera and LED "flash" on the back, as well as a front-facing camera (more on that later). The stainless steel band that surrounds the outside rim of the device is part of an integrated antenna system for improved reception. Both the back and front surfaces have improved scratch-resistant coatings.

Also as rumored, iPhone 4 has four times as many pixels on its 960 x 640 pixel, IPS LCD "Retina" display compared to previous iPhones. That gives the 3.5" display a resolution of 326 pixels per inch, enough to achieve print-like quality for graphics and text. It has an 800:1 contrast ratio, another 4x improvement over the iPhone 3GS. Existing apps will get improved rendering for text and native controls when running under iPhone OS 4.0, though updating custom controls and graphics will be up to developers to get the best results.

"This is going to set the standard for displays for the next several years," Jobs said.

Internally, the iPhone is now powered by Apple's A4 mobile processor, the same snappy processor that powers the iPad. Because the power efficiency of the A4 is combined with a larger battery, Apple claims 40 percent more talk time on 3G—from 5 to 7 hours for the iPhone 4. It gets about 6 hours of 3G browsing or 10 hours of WiFi browsing. Media mavens will get up to 40 hours of music or 10 hours of video playback. The battery is good for 300 hours of standby time.

In addition to the A4 processor and improved battery, Apple is updating several of the internal components. WiFi is upgraded to 802.11n speeds, and the cell radios support up to 7.2Mbps down, 5.8Mbps up HSPA+. Dual microphones are included for ambient noise cancellation. And Apple has added a MEMS-based gyroscope for six-axis motion sensing, in addition to the accelerometer of previous iPhones. New CoreMotion APIs are available in iPhone OS 4.0 to take advantage of the new motion-sensing capabilities.

As we suspected, Apple has added a 5MP, backside illuminating sensor to the iPhone's camera hardware. In addition to vastly improved low-light shots, the camera is also paired with an LED flash. The camera is capable of recording 720p HD video at 30fps, and can use the LED as a "torch" lightsource. Adding to the software features of the camera, Apple has added digital zoom to take advantage of some of those (in many cases) extraneous megapixels. It has also added tap-to-focus for video recording in addition to still image capture.

Along with the improved image capture tools, Apple is launching iMovie for iPhone—a complete video editing environment complete with scene transitions, editable titles, themes, and more. The app will sell for $4.99 via the App Store, presumably when iPhone OS 4.0 becomes widely available.

As for "one more thing," Jobs announced a new video chat feature called "FaceTime." The new feature works between one iPhone 4 and another iPhone 4 over WiFi—so no compatibility with older iPhones, and you won't have to worry about video calls bumping up against AT&T's new data caps. "FaceTime is gonna be WiFi-only in 2010," Jobs explained. "We've gotta work a little bit with the cellular providers to get ready for the future." Apple is making FaceTime an open industry-wide standard, and expects to ship tens of millions of compatible devices (we're guessing a compatible iPod touch is coming this fall) this year.

"I grew up here in the US with The Jetsons and Star Trek and communicators, dreaming about video calling, and it's real now!" Jobs said during a demo with Apple SVP of industrial design Jonathan Ive. Jobs suggested that FaceTime could be embraced by old college buddies or those in long-distance relationships. However, Jobs showed a video of the true target demographic: families with children. Jobs also noted that those who rely on sign language to communicate could benefit from the feature, though a stand would be needed to sign fully with both hands.

Pricing is as expected, with a 16GB iPhone 4 running $199 with a two-year contract (in the US) and a 32GB model selling for $299 with a contract. The iPhone 3GS moves in to replace the iPhone 3G at $99 with a contract. (Expect comparable pricing worldwide depending on contract options.) AT&T is offering customers who would be eligible for a new iPhone within 6 months of June 24 an early upgrade option without a price penalty—a nice move after frustrating many users with recent 3G data pricing changes.

iPhone 4 will be available in the previously revealed white and black colors. Pre-orders begin June 15, with phones shipping June 24 in the US France, Germany, UK, Japan. It will roll out to 18 more countries in July, 24 more in August, and 40 more in September.