Such an unlocked phone means there is no contract and you are free to use it on any supported carrier. For that privilege, it means paying full price for the phone–starting at $649 for the 16GB version.

The reason the price tag is so high is that what keeps the iPhone cost generally low is the fact that the carrier (either AT&T or Verizon) is footing a huge chunk of the cost in return for nailing down a customer for at least two years. With an unlocked phone, the user is picking up the full tab.

The unlocked model is still a GSM phone, so in the U.S., that basically means it runs on T-Mobile and AT&T. And, while it can make calls on T-Mobile, it can only send data over T-Mobile’s old EDGE network, not its 3G network, and certainly not its faster HSPA+ network. It won’t work at all on Sprint, which uses a CDMA network.

That said, if one really wants to buy an iPhone 4 for use on T-Mobile, there is now an officially supported means for doing so.

It also might have some appeal for someone who is still under contract and just got a new phone, or perhaps someone who has lost or damaged their device.

The biggest use for an unlocked iPhone is likely for frequent international travelers. Buying an unlocked model means that those going overseas can just pop in a micro-SIM (the iPhone uses a smaller version of the standard SIM card) for whichever country they happen to be in, avoiding AT&T’s exorbitant international fees.

For true jet-setters, one can actually save money over the long haul, as international calling and data roaming can easily lead to three-figure monthly bills — as many have found out the hard way.

There will be two iPad models–one with Wi-Fi-only and one with Wi-Fi and 3G. The 3G device will come with two plans: 250 megabytes per month for $14.99, and unlimited data for $29.99.

The Wi-Fi-equipped devices will ship within 60 days, the 3G within 90 days. The 3G models are unlocked and they use new GSM micro SIMS. So chances are they’ll just work, quipped Jobs. He added that Apple (AAPL) hasn’t made any deals with international carriers.

Jobs made a point of noting that there are no contracts for the iPad–users may cancel at any time.

And what of Verizon (VZ) Wireless, the carrier pundits were convinced would be supporting both the iPad, and, eventually, the iPhone? Not a mention.

Leave it to Google to compare its most aggressive new product to date with one that often includes meat by-products, bone meal, brewer’s rice, corn syrup and–yum!–“dried animal digest.”

But that’s exactly how the Silicon Valley search giant chose to describe its new Nexus One smartphone in a blog post Saturday.

As in eat its own product! Get it?

Titled: “An Android dogfood diet for the holidays,” the post reads, in part:

At Google, we are constantly experimenting with new products and technologies, and often ask employees to test these products for quick feedback and suggestions for improvements in a process we call dogfooding (from “eating your own dogfood”). Well, this holiday season, we are taking dogfooding to a new level.

We recently came up with the concept of a mobile lab, which is a device that combines innovative hardware from a partner with software that runs on Android to experiment with new mobile features and capabilities, and we shared this device with Google employees across the globe.

While Google (GOOG) did not cite the phone by name in its online missive, a number of sources told BoomTown that the sleek-looking, brown-gray touchscreen device was given to employees at the company’s weekly all-hands meeting Friday afternoon at the Googleplex HQ in Mountain View, Calif., and across the world, ensconced in a white box with the name right on the top.

While the bajillions of Google employees given their early holiday gift were told not to tweet about it or share any information, that’s precisely what they soon did, declaring it delicious.

The Twitter feed, so to speak, that ensued quickly got noticed by the blogosphere–first on Friday night by TechCrunch, which also first wrote about the “Google Phone” last month. (The Wall Street Journal followed up with the name of the phone and other details on Saturday.)

And that is exactly what Google execs meant to happen, of course, by slowly unleashing the Nexus One on the public.

Why? Well, so as to test the waters, presumably, after finding a somewhat tepid reception, so far, from big wireless carriers that might provide service for it.

Google has, of course, talked to them all, because its plan to market the phone depends on cooperation and not disputation with the big telcos.

So far, no one but T-Mobile–the U.S. subsidiary of Deutsche Telekom (DT) that already sells four phones using Google’s Android operating system software–has taken the kibble to be part of a new way of selling mobile devices that the search joint will be trying, according to MediaMemo.

As Peter Kafka wrote:

“But, for sure, Google doesn’t intend to sell its new ‘Nexus One’ phone the typical way, sources familiar with the company’s plans say. Instead, it envisions a scenario where customers who buy the handset on a separate Web site are provided with a list of carriers from which they can make a selection menu-style.”

Google needs cooperation here, because most phones are sold “locked,” which means they work only on the carriers you buy them from. (Sort of like making you join a forced march, but with dropped calls.)

Thus, Google is also trying to create a phone so tasty that consumers demand that wireless networks provide it to them, unlocked and with competitive bidding for service.

That prospect is probably not so yummy to the telcos, because they still mostly operate like Soviet ministries, except they’re not nearly as flexible.

The question is: If Google is successful in forcing the wireless giants from their practice of handing over whatever thin gruel they choose to dish up to consumers, will it result in better phones for all?

Or will Google’s experiment be just that and result in another innovative but failed attempt to change the woeful cell system in the U.S., ending up as another Android phone that still lags behind the Apple (AAPL) iPhone?

We’ll all soon see, but not yet, according to Google, which also coined the disturbing term, “dogfooding,” in its hey-everyone-look-at-me-but-don’t-see blog post.

“Unfortunately, because dogfooding is a process exclusively for Google employees, we cannot share specific product details. We hope to share more after our dogfood diet.”

My dog, Cosmo, is waiting expectantly by his empty bowl.

The number of iPhones bought with the intention of unlocking was significant in the quarter, but we are unsure how to reliably estimate the number. We are unsure when all the recipients will activate.”

–Apple Chief Operating Officer Timothy Cook, Jan. 22

So those “missing” iPhones? They’re not missing at all. They’re unlocked. That’s the opinion of a number of analysts who this week are looking askance at Bernstein Research analyst Toni Sacconaghi’s claim that about 1.45 million phones were “missing in action” at the end of 2007–built but not subscribed to AT&T.

“Some unknown number of iPhones are being unlocked by purchasers and some, probably a larger number, are being unlocked for resale,” said Ezra Gottheil, an analyst at Technology Business Research Inc. “Some are in inventory. Some will be returned. And some are being used for the nonphone features, as iPhone Touches, until the owners can change their wireless contracts. We don’t know the proportions.”

Piper Jaffray analyst Gene Munster offered a similar theory, noting that his recent check of Apple’s retail stores found a significant percentage of consumers to be purchasing multiple iPhones. “The majority of the people who were buying more than one phone were Asian, and they were bringing small buses of people who all buy more than one phone,” he told the New York Times. “With the value of the dollar, the cost of the phone is much less here.”

And Munster’s contention would seem to be borne out by anecdotal reports from abroad. “In my travels around the world, two out of three iPhones I’ve seen outside of the U.S. have been unlocked,” Richard Doherty, director at consultant Envisioneering Group, told BusinessWeek. “In China, nine out of 10 phones are hacked.”