Build an embedded Linux distro from scratch from IBM Developer Works
Might be a bit of Preaching to the Choir here, but thought some might
find this of interest. Registration is required, which I find annoying, but
it is free:
"Learn how to build a custom Linux distribution to use in an embedded
environment, in this case to drive a Technologic Systems TS-7800 single-board
computer. In this tutorial, you learn about cross-compiling, the boot loader,
file systems, the root file system, disk images, and the boot process, all
with respect to the decisions you make as you're building the system and
creating the distribution. "