Apple Inc. (NASDAQ:AAPL)’s hotly anticipated smartphones iPhone 6 and iPhone 6 Plus are now available for pre-order. Online advance bookings kicked off at midnight Pacific Time on Friday, September 12. However, Apple’s site didn’t open for pre-order, and remained down as of 02:14 a.m. PT. The websites of many other telecom carriers are also facing hiccups.

iPhone 6

You can pre-order iPhone 6 using Apple’s iOS store app

AT&T and Verizon stores began accepting advance orders for the iPhone 6 and iPhone 6 Plus at midnight Friday. However, T-Mobile and Sprint sites were down, reports Shara Tibken of CNET. You can purchase the iPhone 6 through Apple’s iOS store app. The app is up. But some users reported issues at times, showing errors or listing all the 5.5-inch phablet models as unavailable.

iPhone 6 Sprint

The 16GB iPhone 6 comes at $199 on a two-year contract. Base variant of the 5.5-inch phablet costs $100 more, i.e., you’ll have to pay $299 for 16GB iPhone 6 Plus. Apple fanatics can place advanced orders through the company’s online store. You can also pre-order through carriers such as AT&T, Sprint, T-Mobile, Verizon and US Cellular. Pre-orders at Apple’s brick-and-mortar retail stores begins at 8:00 a.m. local time on Friday.

iPhone 6 to be the most successful Apple product ever?

Verizon witnessed strong bookings. Less than 20 minutes after the carrier began taking pre-orders, the launch delay for the iPhone 6 Plus was as much as one month. That means if you were lucky enough to place an order at midnight, you’ll likely get your phone around October 19 even though official shipping begins on September 19.

As of 12:30 a.m. Pacific Time on Friday, the delivery date for 16GB iPhone 6 in gold and space gray was October 14. The 64GB and 128GB iPhone 6 models had a delivery date of October 7. There seem to be supply issues that would limit the initial availability. The iPhone 6 could be the most successful smartphone in Apple’s history. The tech giant has reportedly asked its suppliers to manufacture more than 80 million units of the new models by the end of 2014.

UPDATE: Apple Online Store is up as of 3:41 a.m. Pacific Time.