A poster on MacNN forums gave a link to a Japanese page with photos of the internals of the iPod. Pretty interesting. He also provided an English translation of the page's text. Take a look.
The two main components on the iPod's circuit board are TI's TSB43AA82, (a FireWire controller) and PortalPlayer Inc's PP5002B (a multi-processor, ARM-based wonder-chip). Well, now we know the platform!