The European Ramblers Association is a federation of 26 national organisations.
Their website is a good source of information on walking in Europe and gives contact details for their member organisations.
Peak to Peak Trail and Wilderness Links
This site contains links to information about hundreds of trails, clubs and hiking tour operators around the world. It's the most comprehensive such site we've found.
Web Directories for Hiking
The directories below give links to all sorts of hiking sites from around the world.