Wikipedia: Geologic Fault
Hyperlinked, in-depth description of discontinuities in the Earth's crust. Explains the differences between normal, strike-slip, and thrust faults.
Faults and Fault Zones
Photo gallery highlighting a number of different geologic fault features in nature including: normal faults, reverse or thrust faults, strike-slip faults, fault contacts, and fault gouges.
Talk Origins: Thrust Faults
Offers an explanation of the mechanics of motion along thrust faults, with photos and examples of the Lewis Thrust working beneath Chief Mountain in Glacier National Park.
University of Leeds: Faults
Describes faults and stress, thrusts, and soft-linked fault systems. Includes picture gallery.