Grasshoppers of Colorado - a nice site with info on identification, biology, and management
http://www.sdvc.uwyo.edu/grasshopper/ghcotoc.htm

Key to Wyoming Grasshoppers
http://www.sdvc.uwyo.edu/grasshopper/kwgkey6.htm

Field Guide to Common Western Grasshoppers - info on identification, biology, and management
http://www.sidney.ars.usda.gov/grasshopper/ID_Tools/F_Guide/refrence.htm

Grasshoppers of Florida - keys, photos, biology, habitat, etc.
http://entnemdept.ifas.ufl.edu/ghopper/ghopper.html

Orthopterist's Society
http://140.247.119.145/OS_Homepage/

Grasshoppers of the Great Smoky Mountains National Park.

http://www.dlia.org/atbi/species/Animalia/Arthropoda/Insecta/Orthoptera/Caelifera/Acrididae/index.shtml