TOEFL- Test of English as a Foreign Language (http://www.ets.org/portal/site/ets/menuitem.fab2360b1645a1de9b3a0779f1751509/?vgnextoid=69c0197a484f4010VgnVCM10000022f95190RCRD) - provides English proficiency testing services.
Dave's ESL Cafe (http://eslcafe.com) - where English is fun!
ESOL Links (http://iteslj.org/links) - maintained by The Internet TESL Journal, this site has links for students and teachers. Some of their many links include dictionaries, games, idioms and slang, culture, and pronunciation for ESOL students.
Washington Area Teachers of English to Speakers of Other Languages (http://watesol.org) - a non-profit professional organization for teachers of ESOL.
Peace Corps: World Wise School (http://www.peacecorps.gov/wws) - provides students in the U.S. with a view of life in one of the more than 80 countries where Peace Corps Volunteers serve.
Prince George's County ESOL Office (http://www.pgcps.org/~esol) - information about the ESOL program in Prince George's County.