Apple announced today that its "revolutionary" iPhone will go on sale today across the US at 6:00 p.m. local time at Apple retail stores nationwide. All 164 Apple retail stores in the US will stay open until midnight, and customers can purchase up to two iPhones on a first come, first served basis.

“Apple retail stores were created for this moment—to let customers touch and experience a revolutionary new product,” said Ron Johnson, Apple’s senior vice president of Retail. “With our legendary Genius Bar support, free workshops and our One to One personal training, we’re here to help customers get the most from their new iPhone.”

iPhone introduces an entirely new user interface based on a multi-touch display and pioneering new software that allows users to control iPhone with just a tap, flick or pinch of their fingers. iPhone combines three products into one small and lightweight handheld device—a revolutionary mobile phone, a widescreen iPod®, and the Internet in your pocket with best-ever applications on a mobile phone for email, web browsing and maps.

Apple says that  iPhone ushers in an era of software power and sophistication never before seen in a mobile device, which completely redefines what users can do on their mobile phones.

iPhone will be available in a 4GB model for $499 (US) and an 8GB model for $599 (US), and will work with either a PC or Mac.

The Wall Street Journal says that according to one study, 58% of British and 64% of U.S. mobile phone users are aware of the iPhone, and 19 million Americans have expressed interest in buying one. That is remarkable stuff when you consider the iPhone's $499 price, not to mention that even the most successful so-called smartphones are lucky to sell a million units.

At $120.56, Apple's shares are up almost 45% in 2007.

Walter Mossberg and Katherine Boehret of the Wall Street Journal spent 2 weeks testing the iPhone: