Nothing like an overview of historic overviews, especially when it comes to the iPod.
> ipodhistory.com: an entire website dedicated to a detailed history of the iPod.
> Wikipedia/ipod: extensive wikipedia page on iPod history.
> The origin of the iPod: evolution of the iPod (2000-2004) by Lowendmac|Orchard.
> iPod history since 2005: Lowendmac|Orchard also traces the recent history of the iPod, showing the diversification of the product.
> History of the iPod, iTunes & the Music Store by Geofftech, including complete timelines of iPod product releases.
> A brief history of the iPod (2000-2004): by iLounge, includes a look at the packaging.
> Raising the Genius Bar: 7 Years of iPod Evolution: Wired photo gallery of iPod evolution
> Video of the evolution of the iPod by T3 magazine.
> Timeline visualization of the iPod history.
> Why the iPod clickwheel must die: Mark Wilson of Gizmodo analyzes why the iPod's clickwheel UI paradigm cannot be sustained in future iPods (via unpressablebuttons)

Inside look into iPod development
Wired, being iPod-obsessed as they are (not necessarily a bad thing...), have a lot of in-depth articles on iPod history, especially some nice stories on its development.
> Inside look at the birth of the iPod
> The perfect thing: another look at the birth of the iPod.
> Oct. 23, 2001: Now Hear This ... The iPod Arrives: looking back on when the first iPod was launched.

UPDATE
Forgot one: MacWorld iPod Timeline

(Top picture by Hartleyjr.)