ManualsLib - Just enter the keywords in the search field and find what you are looking for!
Manuzoid - Repository that includes user manuals for various products
Manula - Manula is an online software for creating user manuals.
Dozuki - Dozuki is a web-based tool for creating and distributing step-by-step documentation.
ManualAgent - Manuals and guides
Online Manual Service - Workshop Repair and Service Manuals All Makes and Models Free Online