Tools for the 68HC11
from Andrew Sterian (Grand Valley State University):
An Open Source 68HC11 Simulator
PF11 -- An ANS Forth Implementation for the 68HC11
from Tom Dickens (Boeing Corp.):
Lots of valuable info, including HC11 basics and robotics
Miscellaneous:
Freescale AS11 Assembler and Manual
ASM11 assembler from ASPiSYS
Shadow11 68HC11 Assembler, IDE, and Debugger
Forth Compiler