Morgan Stanley analyst Katy Huberty, in a note to clients, has raised her Apple price target from US$275 to $310 per share (from $275), and upped her 2011 iPhone sales estimates to 61.5 million units. She also says Verizon users really want an iPhone.

Huberty told clients — as reported by “Fortune” ( — that:

° The percentage of current iPhone customers planning to upgrade rose from 18% in November 2009 to 58% in March 2010. Huberty estimates that the combination of a growing installed base and a rising upgrade rate could yield 19 million upgrade units in 2011.

° Apple will probably cut the price of the iPhone 3GS to $99. If Apple and AT&T could also find a way to cut monthly service costs to $75 from about $90 today, demand for iPhones would increase by another eight million units per year, Huberty

° According to the Alphawise survey, 16.8% of Verizon subscribers say they are “very likely” to purchase an iPhone when and if it becomes available on their network. This could add another eight million iPhones per year, according to the analyst.