“This is our new baby, I hope you love it as much as we do.”

That’s how Steve Jobs closed his keynote at the annual WWDC conference just before noon PDT in San Francisco’s Moscone Center today. Job’s is now a proud father of four iPhones, and his presentation on the latest addition to the family, the iPhone 4, laid down the gauntlet to all other vendors of mobile software and hardware.

“Stop me if you’ve seen this,” Jobs said as he unveiled the new design, referring to the infamous leaked phone obtained by Gizmodo, “and trust me, you haven’t.”

The iPhone 4 look much like the photos of the leaked phone, but until now we’d seen nothing of the new features it offered. With the same basic shape as iPhones past the most obvious observations to make about the new phone are that it is squarer, significantly thinner–just 9.3 mm thick, the thinnest smart phone yet–and circled with steel. That steel band around the edge is more than just eye candy: as well as providing the basic structure it doubles up as the antenna for the voice, data, and GPS functions. This, Jobs claimed, helped make more room for the bigger battery that allows up to 40 per cent more talk time than with a 3GS.

He spent a lot of time talking about the phone’s screen, the “retina display.” Its pixels are at a density of 324 per inch, making images and text sharp, and curves smooth. As a point of comparison, the standard resolution that photos are printed at is 300 dots per inch. The camera has also been improved considerably, and a smaller camera now features on the front of the phone.

Jobs also revealed that the phone now contains a gyroscope, making it possible to track rotation about any axis as well as acceleration in three directions, enabled by the now-standard accelerometers of previous models.

As usual, though, Jobs saved “one more thing” for the finale. Grabbing an iPhone 4 he dialed long-term collaborator and Apple lead designer Jonathan Ives, and tapped a button to switch to a two way video call.

The feature is called FaceTime, and is built deep into the iPhone 4. Anyone with the phone can instantly switch on video when calling another person with the same device without the need to set up a new account or buddy list. For now it only works on Wi-Fi.

FaceTime is more than just another competitor to Skype, or at least Jobs hopes so. “Starting tomorrow we’re going to make FaceTime an open industry standard,” Jobs said. The bundle of video, audio, and other technologies that make up the service will be put forward to the relevant standards bodies in an effort to establish FaceTime as something that any device or network can support.

“I grew up here in the US with the Jetsons and Star Trek and communicators,” said Jobs in his video call to Ives, “and it’s real now.” Consumers will get to find out for themselves if the new phone really do feel like the future when it’s released on June 24, 2010.