USA links

http://simple.wikipedia.org/wiki/United_States

The United States entry in Simple English Wikipedia. Challenging for pre-intermediate level.

http://www.woodlands-junior.kent.sch.uk/customs/questions/americanbritish.html

Differences in vocabulary between American and British English, grouped into subject categories. Pre-intermediate and above.

http://news.bbc.co.uk/1/hi/world/americas/country_profiles/1217752.stm

United States country profile from the BBC website. Challenging for intermediate level.

More resources:

A MAD Pictorial Map of the United States (journeyintomystery.free.fr)

Explore the States - with an interactive map - (americaslibrary.gov)
Interactive Map of the USA (yourchildlearns.com)

United States of America Geography - information and links - interactive map (kidport.com)
Explore the States - with an interactive map (Textes courts et simples) - (americaslibrary.gov)
Maps of United States National Parks and Monuments (University of Texas)
Exercises :

Guide to offbeat tourist attractions - (roadsideamerica.com)
USA State Map/Quiz Printouts (on the geography of each State) and Answers (enchantedlearning)
USA Label Me! Printouts - to print (enchantedlearning)
USA Quiz - - (lizardpoint.com)
Place the State - (interactive) - (bensguide.gpo.gov)