The iPhone 6 launch already is shaping up to be Apple's biggest.
The company said in a statement Friday that iPhone 6 and 6 Plus preorders have been higher than ever before.
"Response to iPhone 6 and iPhone 6 Plus has been incredible, with a record number of preorders overnight," Apple said.
The demand was so high, Apple's online store and various carriers couldn't keep up. Apple on Friday didn't provide information about thefor more than two hours after the iPhones became available for presale. But the company said preorders are currently available online or through the Apple Store app.
The Cupertino, Calif., company started accepting advance orders for its two new phones -- the iPhone 6 and iPhone 6 Plus -- at midnight PT on Friday. But many sites didn't open for preorders at the planned time, including the Apple Store.
The Apple Store remained down in many regions for more than two hours, but savvy customers could purchase an iPhone through Apple's iOS store app. However, availability was severely limited within hours after preorders started.
A note on Apple's website Friday morning said the iPhone 6 Plus would be available to ship in three to four weeks, while the iPhone 6 would be available in 7 to 10 business days.-- the 5.5-inch iPhone 6 phablet, or phone-tablet hybrid -- is believed to have manufacturing issues, limiting the initial supply that's available.
Worse for some customers was that Apple's representatives weren't easy to get in touch with. The company's text-chat support wasn't available by midmorning Friday, and calls to the company's order support line were answered with an automated message saying calls were higher than normal and a representative wasn't available.
Preorders through Verizon Wireless and AT&T largely started without a hitch at midnight, though some customers on Twitter complained about issues. Those problems were nothing compared with the issues experienced by Sprint and T-Mobile customers. The Sprint and T-Mobile sites were still down for many users nearly two hours after presales were slated to start. Access to Sprint's site faded in and out, while the T-Mobile site continued to display a form to register for a reminder for when the preorders began.
The iPhone 6 has the potential to be the biggest launch in Apple's 38-year history. Applemanufacturing partners to produce about 70 million to 80 million units of its larger screen iPhones by December 30, which is about 30 percent to 40 percent more iPhones than it ordered for its initial run of last year's and 5C.
Ordering more devices to be available could buffer Apple against the supply shortages it has seen with past launches -- though there was still a significant wait time for customers as of midmorning Friday. The company also sets aside allotments for the different days of the preorder process. The iPhone 5, released in the fall of 2012, sold out of its initial supply of preorders in less than an hour. Apple didn't offer preorders with last year's high-end iPhone 5S because of supply constraints, but it did put its cheaper, plastic-encased iPhone 5C up for preorder. The iPhone 5C availability was much better due to lower demand for the device.
The 4.7-inch iPhone 6 goes on sale September 19 in 115 countries, starting at $199 for a version with 16 gigabytes of storage space. The 5.5-inch iPhone 6 Plus starts at $299 for its 16-gigabyte version, $100 more. In the UK, an unlocked iPhone 6 will start at £539, and the iPhone 6 Plus will start at £619.
As of midday Friday, AT&T said on its website that the iPhone 6 Plus would ship between November 2 and 27, while the iPhone 6 would ship in 21 to 35 days. AT&T spokesman Mark Siegel said Friday morning that preorders so far have been better than in the last two years. He added that preorders are "always a dynamic process," including shipping times.
Verizon declined to provide color on preorders aside from pointing out the ship dates -- currently ranging from Sept. 19 to Oct. 7 for the iPhone 6 and Oct. 14 to 28 for the iPhone 6 Plus.
Sprint's site provided a "shipping alert," saying some devices may be delayed. The company said "we'll do our best" to get the iPhone 6 to preorder customers by September 19 but noted that the 64 gigabyte and 128GB models of the iPhone 6 Plus will take up to three weeks to reach customers, and the 16GB version won't ship for four to six weeks.
Sprint said in a statement that it is "very pleased with the interest" in the new phones. "While we do not share pre-order numbers, the response has been strong, and [we] continue to update and monitor all of our sales channels as we work to meet the high volume of traffic," the company added.
T-Mobile, which has similar ship dates as the other carriers, also apologized to customers for any inconvenience and said orders have been processing. "We had incredible demand for Apple devices this morning and some customers may have experienced intermittent technical issues with our iPhone pre-order site," the company said.
The iPhone is Apple's most important device and its biggest moneymaker, accounting for more than half of sales. Millions of customers continue to purchase its older devices, but Apple has been challenged by a trend toward bigger-screen smartphones from Samsung, HTC and others. Introducing larger screens with the 4.7-inchand the 5.5-inch will help it please current customers and possibly tempt some buyers away from its competitors.
The new iPhones are a big jump over the 4-inch screen found in last year'sand 5C. In addition to being slimmer and lighter, both models also include a 64-bit A8 processor with improved graphics, an improved 8-megapixel rear camera, better battery life and an NFC chip that allows you to .
Updated at 2:30 p.m. PT with additional information about shipment dates.