Piper Jaffray analyst Gene Munster says that, based on info from the NPD research group, Mac sales aren't being cannibalized by iPad sales, though iPods are, to some degree.

As reported by "Fortune" (http://tech.fortune.cnn.com/2010/05/17/u-s-mac-sales-up-39-in-april/), the NPD data shows domestic Mac sales up 39% year-over-year for the June fiscal quarter, which will to beat the Street's prediction of around 19%. Munster says that means sales of 3.1 to 3.2 million Macs for Apple's third fiscal quarter.

The NPD data shows iPod sales are down 17% year-over-year. That's worse than the 9% fall-off that Munster had forecast. Based on the data, Apple should sell 9-10 million iPods in the June quarter.

"April NPD data gives us the first sign of the degree to which the iPad cannibalizes iPod or Mac sales," Munster said in a note to clients. "From the early NPD data, it appears that the iPad has a minimal cannibalization impact on Mac sales, and could be slightly cannibalizing iPod sales. Given the [average selling price] (4x) and margin profile of the iPad, we see this as a net positive for Apple's business."