Electronic Design published an extensive article detailing the history of the iPod and breaking down its individual components last month that some how made it under the TMO radar at the time.
Along with photos of every part that goes into the first-generation and third-generation iPods as well as the iPod mini, the article includes a number of interesting details about component revisions the iPod has undergone over time and represents an unique look at what goes into every iPod.
Swapping out the mechanical scroll wheel found in the first-generation iPod to the touch wheel not only provided Apple with a more durable part, for example, but the touch wheelis components were also much thinner and were partly responsible for the slightly more svelte iPods that arrived afterwards. Also, earlier iPods had separate chips controlling audio playback, FireWire, and USB connectivity, but more recent iPods have used a single chip that can handle all three capabilities.
The story mostly focuses on the first three generations of iPods, but also includes details on the tear down of the iPod mini and mentions the 4G and iPod photos models as well.