This section of the US Environmental Protection Agency website contains answers to the following questions: What is acid rain and what causes it? How do we measure acid rain? What are acid rain's effects? How do we reduce acid rain? The section also contains science experiments, learning activities and a glossary.

http://nlquery.epa.gov/epasearch/epasearch?querytext=acid+rain+&fld=&areaname=&typeofsearch=epa&areacontacts=http%3A%2F%2Fwww.epa.gov%2Fepahome%2Fcomments.htm&areasearchurl=&result_template=epafiles_default.xsl&filter=sample4filt.hts  

This project is coordinated by the United Nations Environment Programme Regional Resource Centre for Asia Pacific (UNEP/EAP-AP) and sponsored by the Asian Development Bank. Its website contains information about the project, a list of collaborating organizations, a database of experts, general information about acid rain and related links.

http://www.rrcap.unep.org/geo1/ch/ch2_7.htm 

This website contains games, activities and an acid rain activity book.

http://www.epa.gov/acidrain/education/site_kids/ 

Technically speaking, acid rain can refer to any kind of acidic precipitation, though this article focuses on rain itself. In ordinary circumstances, almost all rain is acidic to some degree because of the presence of nitrogen and carbon dioxide in the earth’s atmosphere.

http://www.shadecomforts.com/education/acid-rain-learning-center.html 

This section explains what acid rain is; its effect on aquatic ecosystems, soils, plant growth, buildings and materials, and health. It contains a list of resources (data and maps, laws and treaties) and educational material.

This section explains what acid rain is; its effect on aquatic ecosystems, soils, plant growth, buildings and materials, and health. It contains a list of resources (data and maps, laws and treaties) and educational material. 

This site, developed by the National Oceanic and Atmospheric Administration (NOAA) and the Institute of Marine Research (IMAR) from the United States of America, contains eutrophication-related definitions, publications, data, models and graphics.

http://www.eutro.org/