SAN JOSE, Calif. – For the Apple iPhone’s indefatigable zealots, Thursday was the Fourth Coming.

After a tidal wave of prelaunch hype remarkable even by Apple standards, the iPhone 4 was unveiled to the world at large and to the crowd that had been gathering outside the Los Gatos, Calif., Apple Store for nearly 24 hours.

Atop all that buzz was FaceTime, the new phone’s video-calling feature that brought David Rietdorf, 28, and his brother Ryan, 26, to North Santa Cruz Avenue and to the head of what would turn out to be a very long line of anxious customers by Thursday morning.

“People thought we were crazy to camp out here since Wednesday morning, but I wouldn’t have missed this chance for the world,” said David, a San Jose paramedic whose brother flew in from Arizona to join him in fraternal purchase. “This phone is just gorgeous, and the video calling will bring my brother and me even closer together.”

The excitement in downtown Los Gatos, where about 500 people streamed down the sidewalk in both directions, was mirrored across the county as the new iPhone, the fourth in four years, was released.

It was a hit before the world even saw it — AT&T says it received 10 times as many pre-orders as it did for the iPhone 3GS last year. Apple processed 600,000 requests before the ordering system broke down. Some analysts predicted Apple would sell a million iPhones on Thursday alone.

Prelaunch hype was elevated by the early release of photos of the prototype in April after an Apple employee mistakenly left it behind at a Redwood City, Calif., bar.

The tech-device blog Gizmodo got hold of it and published details and photos — a leak that ultimately sent the hype even higher.

Of all the features that customers said they lusted after, from the higher-quality screen to the longer battery life to the HD video recorder, it was FaceTime that seemed to have sent Apple fans into a frenzy of consumption.

“Star Trek,” said iPhone fan Chris Diskin, “has arrived.”