• by Mark Walsh  @markfwal, September 3, 2009

Android is invading America. Sprint Thursday announced plans to launch a smartphone next month based on Google's Android mobile operating system. With the HTC Hero going on sale Oct. 11, Sprint will become the second major U.S. wireless carrier after T-Mobile USA to roll out an Android phone.

But it won't be the last. Motorola plans to announce plans for its own Android phone next week, and T-Mobile and Verizon Wireless are expected to sell Motorola Android phones by year's end. It all adds up to a bigger mobile footprint for Google and Android in the U.S. market.

"The name of the game for Google is to spread its tentacles across the U.S.," said Ramon Llamas, an analyst at market research firm IDC. "It's had the relationship with T-Mobile, but it can't rely on a single carrier alone, and the No. 4 U.S. carrier at that."

Launched last November, T-Mobile's G1 sold more than 1 million units, getting the Android franchise off to a solid start. The carrier's follow-up Android phone -- the myTouch -- hit store shelves only about a month ago. But Google has made clear that its ambitions for Android are much, much bigger.

"A million customers? Not that interesting. Ten million? Not that interesting, but heading in the right direction. A hundred million customers starts getting interesting," Andy Rubin, Google's mobile platforms vice president, told Fortune senior writer Jon Fortt in July, speaking about Android. "That's why we focused on the cell phone first -- it's the biggest volume opportunity."

The more mobile customers, the bigger the audience for its host of applications and ad programs. But Android has a long way to go to catch up with the iPhone, which dominates mobile advertising among smartphones. The iPhone OS accounted for 60% of smartphone ad impressions in the U.S. in July compared to only 12% for Android, according to the latest data from mobile ad network AdMob.p> The expansion of Android phones could also give a boost to Google's mobile app storefront -- Android Market -- which so far offers only a fraction of the 70,000 titles in Apple's App Store.

Of course, a lot also depends on the Android phones themselves. Llamas pointed out that consumer expectations for new smartphones have been raised by a steady stream of new and upgraded models from Apple, BlackBerry-maker Research in Motion and Palm. "People are paying attention not just to how it looks and feels but what the experience is all about," he said.

To that extent, he adds that Sprint's Hero, initially unveiled by HTC in June, appears to meet the current standard for smartphone capability. The phone's signature feature is the HTC Sense user interface, which allows users to populate the home screen with customizable widgets from work email to Twitter to weather and maps.

The touchscreen Hero, which will sell for $180 with a two-year contract and after a mail-in rebate, also includes features like a 5-megapixel camera, GPS. WiFi capability and expandable microSD memory.