It’s indisputable that Verizon is going to sell a lot of iPhones when the device finally arrives on its network. The question is how many? And the answer is as varied as the research houses trying to pinpoint the number. On the low end, analysts have been calling for nine million, and at the highest end, 12 million.

Until today, when R.W. Baird & Co. analyst William Power reset those parameters with a bullish new potentiality: 23.8 million iPhones sold to Verizon subscribers in the first year.

That’s about double the top end of the range I mentioned (it’s also more than a quarter of Verizon’s current subscriber base). But according to Power–who cautions that this is a “directional number” and not a forecast (there are constraints around how many devices Apple can actually ship)–a recent Baird survey of 1,000 smartphone users supports it. From the survey:

• 29 percent of current Verizon feature phone owners said they will “probably” or “definitely” upgrade to the Verizon iPhone in the next three months. The carrier has roughly 64 million postpaid feature phone users, so that’s 19 million potential iPhone upgrades, assuming eligibility.
• 25 percent of Verizon’s current smartphone users said they will “probably” or “definitely” switch to the iPhone. That’s 4.8 million additional potential iPhone sales, again assuming eligibility.

Grand total: 23.8 million potential Verizon iPhone sales–from the carrier’s installed base alone. Add to that the 5.6 percent of current AT&T iPhone users who told Baird they planned to switch to Verizon and that number rises to nearly 25 million.

Which sounds fantastical, seemingly even to Power, who is standing by his current forecast of 10 million iPhone activations at Verizon. But it does suggest, strongly, that demand could be far greater than anyone has anticipated.

That’s great for Verizon (though perhaps less so for its network) and even better for Apple. Not too bad for AT&T, either. Doesn’t bode well for Android handset makers like Motorola Mobility, though. As CEO Sanjay Jha said during an earnings call yesterday, the company has already seen a slowing of device shipments around news of the Verizon iPhone. “Since the announcement of the iPhone, we have seen some slowdown in our sell through of devices at Verizon,” Jha said. “There was anticipation of devices coming to Verizon even prior the announcement of the iPhone.”

Below, a carrier-by-carrier breakdown of interest in the Verizon iPhone. Each pie chart represents the base of subscribers at each carrier who plan to purchase a smartphone in the next three months. Note: the 25 percent / 29percent numbers above refer to the percentage of the total base of Verizon respondents (i.e. Verizon respondents who plan to purchase a smartphone in the next three months plus those who don’t).

In a research note this morning, Piper Jaffray’s Gene Munster increased his iPhone sales estimates for both the June and September quarters to 9.5 million from 8.5 million, arguing that Apple (AAPL) will likely sell one million iPhone 4s during the device’s first three days on the market. He also noted that the six-month extension on upgrade eligibility pricing that AT&T (T) is offering should significantly juice demand.

“AT&T has pulled forward existing iPhone users’ eligibility for upgrade pricing by up to 6 months,” Munster wrote. “In other words, all early iPhone 3GS buyers will be eligible for upgrade pricing on the iPhone 4, but last year early iPhone 3G buyers were not eligible for the iPhone 3GS upgrade pricing. Specifically, we believe that the 8.4m iPhone users activated at AT&T between the Sept-08 and Jun-09 quarters will be eligible for upgrade pricing.”

Over at UBS, analyst Maynard Um went Munster one better. “We expect the iPhone 4 launch to be larger than the iPhone 3GS launch last year which sold 1 million units in its first 3 days. Although dependent upon initial supply, we see the potential for Apple to sell 1 million units on the first day of launch.”

At this point, Um’s scenario seems the more likely. As of this writing, Apple has taken pre-orders for more than 600,000 iPhone 4s. With more than a week to go until the official launch, it’s entirely plausible that the company will hit that number. And if launch day walk-in sales are anything like they’ve been in the past, it may far exceed it.

In your review of the new iPhone 3GS, you said that AT&T had changed its upgrade policy so some buyers of the previous model could get the new-customer price earlier than planned. Can you explain this in more detail?

Almost all cellphones in the U.S. are subsidized by the carriers to bring down prices. Typically, existing customers—who have already benefited from a subsidy—can’t upgrade at the lower new-customer price (in this case $199) until they reach a point in their contracts where this subsidy has been recovered. These dates vary, based on a formula that takes into account things like the customer’s monthly spending rate.

When some early adopters of the 2008 iPhone model, the 3G, discovered they wouldn’t immediately qualify for this $199 “standard upgrade” price—the same as the new-customer price—they got angry. So AT&T made a concession, but only a partial one. It declared that any customer who had been told he or she couldn’t get the $199 price until sometime in July, August or September of 2009 would in fact now be able to qualify for that lower price starting on the first day of availability.

This concession doesn’t apply at all to owners of the original 2007 iPhone, or even every owner of the 2008 3G model. And it isn’t based on when you bought your 3G, but when the system told you that you could buy the new model at the “standard” upgrade price of $199. You can check the price AT&T or Apple will charge you for an upgrade by going to www.att.com/iPhone and clicking on “Check upgrade eligibility.”

I’ve recently heard that the new Palm Pre smart phone is unable to import data from the old Palm Desktop program. In other words, if you have Palm Desktop filled with data from a previous Palm model, you’ll be unable to get that data into your new Palm Pre. Is this true?

No. While the Pre isn’t designed to repeatedly sync with the old Palm Desktop software, Palm does offer a program, for Windows and Mac, that will perform a one-time import of your old data from Palm Desktop. It can also do a one-time import of data from certain other desktop programs as well, including Microsoft Outlook on Windows, and iCal and Address Book on the Mac. This program will help you move your data to one of the online services, such as Google, with which the Pre is designed to sync continuously. The software is called the Palm Data Transfer Assistant and is free at http://bit.ly/3lIaZ.

I am contemplating purchasing the 17” MacBook Pro rather than the 13” or 15” models because the antiglare matte screen is offered only with the 17”. How bad is the glare on the smaller screens and how cumbersome do you find the larger 17” MacBook Pro?

For a laptop of its size, the 17” MacBook Pro is remarkably thin and light. But I did find it cumbersome to use in coach seats on airplanes and to cram into small briefcases. As for the glossy screens, which are now the most common option on many laptops, they bothered me at first, but I don’t notice the glare now. However, both of these are personal issues. So my suggestion is to go to a store and see for yourself.

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