Hi,
I use "C A Reference Manual" by Harbison and Steele Jr as my programming reference for the C programing language. Looks like the 5th edtion is the latest.
In additon, you might start with the examples included with CodeWarrior. Reading other people's code, and being able to modify it, is a good way to learn embedded programming. Get some hardware for a 9S08 and have some fun with LEDs, serial ports, ADCs, and anything you can wiggle on the EVB.
There are some rappid application development tools (i.e. Processor Expert) that come with CodeWarrior for MCU v6.x that generate C code for you. This can be another source of processor/peripheral specific application code for you to work with. The guys who develop Processor Expert, Unis, have excellent coding structure, format, and comments. You may have a different style, but their code is worth looking through.
Don't be afraid to hack, hack, hack, and hack some more, until you get it right. Read the data sheet, and try to figure out how things work before you jump into coding.
Have some fun while you are at it!
- Rick