Apple could see its second-quarter sales hit $24.42 billion, according to the latest forecast from J.P. Morgan analyst Mark Moskowitz.

In a research note released today, Moskowitz upped his sales estimate from $23.83 billion previously, due in part to strong demand for the iPhone. The analyst now believes Apple sold 18.4 million iPhones for the quarter, up from a previous forecast of 16.6 million. Shipments of the iPhone were higher than expected, helped by the Verizon iPhone, which may have grabbed 2 million or more customers over the quarter. But a broader availability of the iPhone's GSM version also contributed.

Moskowitz's revised sales estimate is higher than that of Wall Street analysts in general, who are eyeing second-quarter sales of $23.26 billion. For the full fiscal year 2011, Moskowitz raised his forecast to $104.04 billion from $101.49 billion previously. Wall Street is looking for annual sales of $100.73 billion.

The analyst did drop his quarterly estimate for the iPad 2, now eyeing unit sales of 5.4 million versus 6 million previously. Moskowitz attributed the lower forecast to a temporary stall in shipments of the new tablet but doesn't see this as a long-term issue. For calendar year 2011, he now expects Apple to sell 31.3 million iPad 2s, up from an earlier forecast of 29.1 million and sees the company continuing to lead the tablet market this year and next.

The Mac is also likely to play a role in in boosting Apple's second-quarter results. Based on the momentum of the Mac, especially the MacBook Air, Moskowitz raised his sales estimates for the Mac slightly to 3.89 million units from 3.85 million previously.

On the downside, the analyst expects the iPod to contribute less and less to Apple's bottom line. With the iPhone and iPad cannibalizing sales of the iPod. Moskowitz is now forecasting iPod unit sales of 9.1 million for the quarter, down from a prior estimate of 9.6 million.

For its first quarter, Apple reported record revenues and earnings. The company reports its second-quarter results on April 20.