Apple's current Back to School promotion -- in which students can pick up an iPod nano or touch for free, alongside a new Mac -- might have more significance than normally attributed to it, write analysts with Piper Jaffray. The firm notes that at $299, the cost of a Touch is a significant hit for Apple, which in past years has limited its iPod rebates to $199. This is likely one driver of Apple's decreased gross margin predictions, set to slide to 31.5 percent in September and eventually 30 percent during FY09. By contrast, margins reached 35 percent in the June quarter.

Free Touches are expected to increase Mac sales during the second half of 2008, though, and the other factor in margins is believed to be Apple's so-called "product transition," which Piper argues will consist of lower-cost Macs and iPods announced at a press event in September. Apple has yet, however, to announce any such gathering.