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.
Microcomputer Architecture and Programming. The 68000 Family, First edition, John F. Wakerly. Pub Wiley, 1989.