Fast passes can be found at all the big rides, like indiananjones, space mountain, big thunder, radiator springs. Racers, etc.... They are totally free. What you do is find the fast pass kiosk (usually by the ride) and enter your park ticket. The fast pass machine will suck in your park ticket, and then issue you your ticket back, as well as a fast pass voucher for the ride... The fast pass will have an hour time window on it of when you can come back (say between 10:30-11:30). When you come back at that time you can show your voucher to the cast member at the fast pass line and they let you in. Now you get to skip the stand by line and wait in the much shorter fast pass line... So basically you have been "waiting" for 1-2 hours like everyone else, but you got to do other things in that time besides just waiting in line, like getting lunch, shopping, or doing other rides.
You can only hold one fast pass before that time window... So if your time window ends at 1130, you would have to wait until then before getting another fast pass.Except WOC, which you can get at anytime.