Ever wanted to build your own guitar? Read on!

Understanding Guitar wiring - This helpful page from StewMac (Stewart-McDonald - A luthier supply complany) explains how pickups work, various switches used in electric guitars, capacitors, shielding and many other fundamental concepts. Great for understanding why you do what you do!
Wiring link - here
More wiring stuff here
Wiring variations
This page table provides wiring diagrams for countless possibilities of switches, pickups etc.