Books
Here's a list of books that relate to the 680x0 family, both interfacing and programming:
Microprocessor Systems Design. 68000 Hardware, Software and Interfacing, 2nd edition, Alan Clememnts. Pub. PWS-Kent 1992.
M68000 8-/16/32-Bit Microprocessors Programmers Reference Manual, Fifth edition, Motorola. Pub. Prentice-Hall 1986.
Programming the M68000, 2nd edition, Tim King and Brian Knight. Pub. The Benjamin Cummings Publishing Company Inc. 1986.