Google’s army of Android phones managed to pass the iPhone in market share in the U.S. for the first time last quarter.  NPD analyst Ross Rubin attributed the strong sales to Verizon’s buy-one-get-one deals.  Android phones have been discounted heavily as well.

NPD’s numbers come from self-reported online consumer surveys (corporate sales aren’t included), which may not be indicative of raw numbers.

Android is now on all U.S. carriers and is the flagship smartphone on T-Mobile and Verizon.  Verizon (VZ), who many view as the nation’s best network,  just launched the HTC Incredible and had sold Motorola (MOT) Droids as fast as Apple initially sold iPhones.  Meanwhile Sprint (S) will be announcing the HTC Evo 4G this summer, considered by many to be the premier Android phone.

Even Apple’s iPhone U.S. carrier, AT&T (T), carries Android phones, and Google (GOOG) offers a Nexus One with radios specifically for AT&T’s network.

Android’s rise has been dramatic, as seen below.

Apple only releases one iPhone a year on just one network, AT&T.  Most Apple customers understand this and wait for the summer to upgrade their phones.  Many iPhone contracts will come up for renewal this July.

Apple has indicated that it will stay exclusively with AT&T in the U.S. in the near term, and the 4th generation iPhone has been spotted by technology blog Gizmodo.  Apple will likely announce and officially reveal that iPhone next month at its Worldwide Developers Conference.

NPD shows that Blackberry (RIMM) still leads the pack with 36% of the smartphone market, though it has fallen significantly  in the last two quarters from its 50% pedestal.

Methodology: The NPD Group compiles and analyzes mobile device sales data based on more than 150,000 completed online consumer research surveys each month. Surveys are based on a nationally balanced and demographically-representative sample, and results are projected to represent the entire population of U.S. consumers. Note: Sales figures do not include corporate/enterprise mobile phone sales.