iPhone Tops Sales Charts at Each of Its U.S. Carriers - John Paczkowski - Mobile - AllThingsD

Check the article link for more details; overall, at least in the U.S., the smartphone market is Apple + Samsung + other, and the "other" momentum appears to be fading

"“Our March checks indicated the iPhone continues to extend its market share gains,” Canaccord Genuity analyst Mike Walkley writes in a note to clients today. “In fact, we believe iPhones are outselling all other smartphones combined at Sprint and AT&T and selling at roughly equal volume to all Android smartphones at Verizon.”
That’s pretty astonishing, all things considered. The iPhone does have some formidable competition. Indeed, Walkley notes that Samsung’s Galaxy S II is selling quite well at AT&T and Sprint, while its Samsung Galaxy Nexus is doing well at Verizon."

iPhone Tops Sales Charts at Each of Its U.S. Carriers - John Paczkowski - Mobile - AllThingsD