J.P. Morgan analyst Mark Moskowitz has upped the firm’s shipments of the iPhone in the December quarter to 28 million (up from 25.3 million), he said in a note to clients — as reported by “AppleInsider” (http://www.appleinsider.com).

He was revved his company revenue estimates to US$38.69 billion. Moskowitz says U.S. carriers have been “surprised by the strong uptake” of the iPhone 4S, as well as the lower-priced iPhone 4 and 3GS models. The older iPhone models are also expected to aid Apple’s penetration in emerging markets such as China.

According to the analyst, sustained demand for all three current iPhone models will push Apple’s revenues up to $38.69 billion with $9.87 in earnings per share this quarter. The firm’s previous estimate stood at $37.26 billion and $9.45 EPS (earnings per share). Wall Street consensus puts Apple’s revenue for the quarter at $38.02 billion and $9.78 EPS.