Google&39's Andy Rubin shows off an unreleased Motorola Android tablet at D: Dive Into Mobile.

A 3D version of Google Maps will accompany a Motorola tablet running Honeycomb, the next version of Google's Android, according to Google's Andy Rubin.

Rubin showed off the unreleased prototype tablet at the opening session of D: Dive Into Mobile in San Francisco today, the same day that the company announced plans to ship Gingerbread, Android version 2.3. Honeycomb and the Motorola tablet will arrive at some point next year, Rubin said, showing off the Google Maps application and eliciting more than one "oooh" from the crowd of mobile professionals.

He declined to provide any further details about the tablet.

Rubin was grilled on many Android-related topics by hosts Walt Mossberg and Kara Swisher of D: All Things Digital. He was granted a few minutes to show off the Nexus S, the new phone announced by Google this morning that will run Gingerbread on a Google-specified and Samsung-built smartphone.

When pressed on Google's Nexus strategy in general, which has evolved in starts and fits throughout 2010, Rubin admitted "we bit off a little more than we could chew" when it came to trying to promote the Nexus One as a start-of-the-art Google-designed phone and the centerpiece of a smartphone-buying strategy that was intended to match intriguing phones with the carrier of one's choice, which is a popular approach in the U.K., he said.

However, U.S. carriers were less supportive of the idea. Google dropped the idea of the Web-only store for the Nexus S, scaling back its ambitions and working with Best Buy to distribute the phone, which is available either unlocked or with a two-year contract for T-Mobile's network.

The carriers have a fair amount of control over how Android is presented to consumers, but that was always Google's intention, Rubin said. Google has been criticized for allowing carriers to clutter up the Android interface with pet apps that Mossberg charitably referred to as "craplets," but Rubin said the carriers are starting to understand those practices alienate consumers, and he implied that Android carriers are rethinking that strategy.

Still, "those guys would be commoditized if I forced them to all look the same," Rubin said. One of the reasons Android has done as well as it has is because carriers and handset makers want an alternative to Apple's iPhone or Research In Motion's BlackBerry, but they don't want to turn into the HP, Dell, and Acer of the PC world, beholden to Microsoft and Intel for innovation and left with no other way to distinguish themselves from the competition other than price.

Despite the rancor that often characterizes the once-close relationship between Google and Apple, Rubin took time to praise Apple for what he said Apple has done right, namely services like the App Store, and even going so far as to acknowledge that its developer program is relatively "open," a word that Google's Vic Gundotra and CEO Eric Schmidt never use in referring to Apple in its approach toward third-party software development. A true Googler, Rubin went on to point out that Google is more "open" in its approach to how it allows outsiders to review the source code of Android in addition to unrestricted development. Still, it was a bit surprising to hear a senior Google executive use the word "open" with respect to Apple.

In further discussion about the competition, Rubin said Microsoft's Windows Phone 7 was "a good 1.0 product," but he said if he was asked for advice, he would implore them to find a better way to allow the differentiation he referred to earlier among its hardware partners. The problem for companies like Microsoft, Nokia, and even RIM is that much of their code is simply old, dating back from a time before the smartphone revolution was fully realized by Apple's iPhone, he said.

Rubin was very coy about discussions that Google may or may not have had with Nokia about the possibility of the world's largest smartphone vendor adopting Android under its new leadership, after an outgoing Nokia executive compared the strategy of using Android to that of young boys urinating in their pants to stay warm in cold weather. When pressed, Rubin declined to comment on any specific negotiations in either Finland or Mountain View, refusing to confirm or deny that talks had been held.

Later, Rubin admitted that Android could do a better job when it comes to usability, lending weight to the notion that Android is an engineer's operating system as opposed to one designed for tech novices. He promised that future releases such as Honeycomb would do a better job of exposing vital functions to users without requiring them to navigate through a sea of menus.

"You'll see the fruits of that investment in the tablets first, and then the phones," Rubin said. "We're aware of the problem and we're going to do better."

Updated 9:20 p.m. PT throughout with additional information from the event.