PICmicro MCU16/17 Microcontroller Data Book and Microchip Embedded Control Handbook. Both books are obtainable from Arizona Microchip and their distributors.

Microchip Technical Library CD-ROM.
Obtainable from Arizona Microchip and their distributors.

Everyday Practical Electronics.
The No.1 monthly magazine for electronics technology and computer projects, with frequent articles on PICmicro MCUs in practical constructional designs.

PICmicro data sheets
Click here to open the PIC16F8X data sheet in Adobe Acrobat format.

Up-to-date versions of the PICmicro data sheet can be downloaded from Arizona Microchip's web site:

http://www.microchip.com