Jewish Reconstructionist Federation

The Jewish Fund for Justice
http://www.jfjustice.org
JFJ has a number of educational resources, including many based around the holidays. In particular, they have created an innovative tzedekah curriculum that deals with poverty issues from a social change perspective. JFJ also runs a program called the Youth Endowment Fund (YEF) which gives kids (under 21) the opportunity to financially help struggling kids in America fight poverty. Kids, their parents, or grandparents, or whoever can can establish a YEF by making a minimum gift of $1000. Once a year they can choose which youth organizing group gets to receive the interest earned from their YEF.

The Funders Collaborative on Youth Organizing
http://www.fcyo.org/
This is a collective of national, regional and local foundations and youth organizing practitioners dedicated to advancing youth organizing as a strategy for youth development and social change.

SocialAction.com
http://www.socialaction.com
This is perhaps the best Jewish social justice website out there, with a wealth of resources, articles, book reviews and other information. It's worth spending a little while surfing around it to see what's there. They have links on the main page to sections ("channels") for teens as well as younger kids.

Jvibe.com
http://www.jvibe.com/jvibeaction/
This is the teen 'zine sister website of socialaction.com. It has an online and print version and includes sections on pop culture and Israel as well as social action.

The Heifer Project
http://www.heifer.org/
An innovative approach to ending poverty and hunger worldwide by providing needy families with actual animals to raise and instruction in sustainable agricultural practices, as well as requiring them to pass on the favor. Kids from the religious school at JRC in Evanston, IL have been involved with them and have raise money to purchase several animals for villages in Africa. They've been able to tie it nicely into lessons on Noah's Ark.