Microchip

http://www.microchip.com/

Manuals & Tutorials

MPLAB® Version 5.40

MPLAB IDE Integrated Development Environment Overview

http://www.microchip.com/14010/tools/picmicro/devenv/mplabi/index.htm

specs for the PIC16F873

http://www.microchip.com/14010/helper.htm

Implementing a Bootloader for the PIC16F87X - documentation

Implementing a Bootloader for the PIC16F87X - source code

http://www.microchip.com/14010/appnote/category/16f87x/index.htm