A good book to start with is "short course 8051/8052 microcontrollers and assembler" Written by M.Ohsmann.
This is a book from "elektor electronics". ( ISBN 0-905705-38-6 )

It has a design for a cpu-board (schematics & PBC-lay-out) as well as an experiment-board (containing RS-232,midi, LCD, A/D, digital I/O).

In this book every aspect is also accompanied with some examples, which work directly when using the above board.

I found it a very helpfull book. It helped me tremendously!