You can find some eBook resources on how to start and what to read.

PIC microcontrollers
Purpose of the book is not to make a micros expert out of you, but to make you equal to those who had somebody to ask.

Programming PIC Microcontrollers in BASIC
The complete BASIC programming language manual for PIC micros! Many examples with schematic, commented in details.

A Quick Guide to Microcontrollers
A great quick tutorial for the PIC to get started.

Guide to use the PIC
I will introduce the electronic circuits making which used the PIC(Peripheral Interface Controller) which is the one-chip microprocessor. I will make this page for the beginner of PIC including me.

Using Macros with PIC Microcontroller
Is an great article about using macros with the PIC, by Myke Predko, the author of “Programming and Customizing the PIC Microcontroller”, the “Handbook of Microcontrollers”

Programmierkurs für PIC-Mikrocontroller in C (CC5X Compiler)
Is a German book about programming the PIC Microcontroller in C, with a great number of examples

Introducing the PIC’84
A great introduction text that will help you to jump into the world of PIC Microcontrollers.