Besides the product transition, Oppenheimer says margins are also being impacted by a back-to-school promotion that gives Mac buyers a free iPod and by accounting charges related to the iPhone. The company says rising component prices and product development costs will continue to put pressure on margins into next year. Oppenheimer says Apple is also keeping an eye on the current economic climate, but so far the downturn has had little impact on sales.

Apple's iPod sales remain brisk at 11 million, although customers seem to be snapping up a lot more of the cheaper Shuffle models. Oppenheimer says the company is also seeing "some cannibalization," of iPod sales by customers who buy an iPhone instead. But he said if "there's going to be cannibalization, we'd rather it be by the iPhone."

Reaction from Wall Street was less than positive. Even though Apple reported its best June quarter earnings ever, investors appeared focused on the future, with the after-hours stock price down nearly 10 percent. Still, Oppenheimer says the outlook is largely positive, with new products in the pipeline. And it may be important to note that Apple has a long record of issuing conservative earnings forecasts, only to top them.