ATLANTA (CNN) — Pre-order response to the iPhone 5 has been massive, outstripping expectations of analysts, who were bullish on Apple's latest smartphone to begin with, and apparently of Apple itself.

Apple received more than 2 million pre-orders in the first 24 hours, double the number it got for last year's record-setting iPhone 4S release, the company said.

Apple is also updating its phone software and will ditch Google Inc.'s mapping service for its own. Besides appearing on the new phone, the new iOS 6 software will be a free upgrade for older devices, including the past three iPhones and the past two iPads. That upgrade will be available starting Wednesday.

Apple's initial promise to ship pre-ordered phones in a week, the same day they become available at Apple Stores and other retailers, was pushed back just an hour after pre-orders opened up at midnight Thursday.

Now, it could take up to a month for the phones to ship. Wednesday morning, Apple's online store said a pre-ordered iPhone 5 would be shipped in three to four weeks.

Apple hasn't released up-to-date pre-order numbers. But Piper Jaffrey analyst Gene Munster estimates the company could announce as many as 10 million sales by Monday morning. His "worst case" scenario is 6 million.

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Apple: iPhone 5 orders topped 2M in 24 hours

Orders for the iPhone 5 topped 2 million in their first 24 hours, more than double the amount of its predecessor over the same period.

Analyst Shaw Wu of Sterne Agee made light of initial reviews from the tech press that suggested the phone wasn't as new or different as Apple claims.

"We find it interesting that many tech blogs and reviewers panned the iPhone 5 saying it 'lacked the wow factor' similar to the iPhone 4 that was plagued by 'antenna-gate' and the iPhone 4S which was a relatively 'minor' and 'disappointing' update with Siri as the key new feature," he wrote. "The previous iPhones went on to sell record number of units and we believe iPhone 5 will likely see a similar result."

Brian White of Topeka Capital Markets agrees, saying his initial prediction of 5.5 million sales over the weekend was probably way too low. Apple's stock, which crested at $700 per share this week, could spiral to a mind-boggling $1,100 by this time next year, he said.

Some folks were already seeking to cash in on the wave of popularity Friday -- before they even got their hands on one of the phones.

On Ebay, an unlocked, 16GB iPhone 5 had been bid up to more than $1,200 on Friday, presumably by folks in countries where the smartphone won't be released for weeks. Others were selling at prices ranging from $650 to $1,000.

The iPhone 5 will be available at Apple stores in the United States, which will open at 8 a.m. Friday. Also selling them will be AT&T, Sprint and Verizon stores and some Best Buy, RadioShack, Target and Walmart locations.

As the debut nears, Apple has dropped the price of the iPhone 4S to $99 and the iPhone 4 is now free with a mobile service e-contract.