Where to Preorder the New Apple iPhone 6 and iPhone 6 Plus

— -- Ready, set ... go!

The hotly anticipated iPhone 6 and iPhone 6 Plus are available today for preorder.

The phones officially went on sale at midnight on Apple.com and on the websites of various wireless carriers. Apple fanatics can also place their orders in-store at big-box retailers, including Best Buy, Walmart and Target.

Customers who visited the online Apple Store Friday were met with a message: "We'll be back," the message reads. "We're busy updating the Apple Store for you and will be back soon."

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Devices won't reach consumers until Sept. 19, according to Apple.

The most obvious physical difference among previous iPhones and the latest devices is the screen size. The iPhone 6 is 4.7 inches, while the iPhone 6 Plus measures 5.5 inches diagonally, giving Samsung, which has dominated the giant phone market, some competition.

The iPhones are also packed with new features, including "reachability." With a double touch, the display can slide down so users can reach "anything" at the top of the phone, an ideal feature for multitasking.

Apple Pay, the company's digital wallet that is aiming to be a credit card killer, will also be supported on the new iPhones.

Apple uses a new chip called the Secure Element, which is embedded in the new devices. The chip stores users' encrypted payment information and allows them to pay for items with a simple swipe.

McDonald’s, Subway, Whole Foods and Apple retail stores are among the retailers that will accept Apple Pay when it launches next month. McDonald's said all U.S. locations will accept Apple Pay after it is live.

The iPhone 6 starts at $199 for a 16 GB configuration, $299 for 64 GB and $399 for a 128 GB configuration, with a two-year contract.

The iPhone 6 Plus starts at $299 (16 GB), $399 (64 GB) and $499 (128 GB). Both phones come in three colors: gold, silver and space gray.