Below is a list of resources, print and electronic, that might be helpful in researching your essay. The list is by no means exhaustive, but should provide some good background to get you started.
Capps, Randy, Michael Fix Everett Henderson and Jeffrey Passell. "Civic contributions: taxes paid by immigrants in the Washington, DC, metropolitan area." Community Foundation Study, May 2006.
Eckstein, Zvi. "Immigrants in the labor market: Impact, integration and methods." PowerPoint prepared for the 2001 Annual Conference of the European Society for
the Population Economics, Athens, June 14-16, 2001.
Lowenstein, Roger. "The immigration equation." New York Times (magazine), July 9, 2006.
(Article summarizes the economics of immigration, focusing on the debate between two noted economists. It's an excellent starting point for research.)
Kronholz, June. "Immigration's latest debate: Is U.S. big enough?" Wall Street Journal, July 11, 2006.
Lyman, Rick and Brenda Goodman. "New data shows immigrants' growth and reach." New York Times, Aug. 15, 2006.
Magnusson, Paul. "Whipsawed on the border; As illegals pour in, the interests of business and ire of citizens are colliding." BusinessWeek, Oct. 10, 2005.
McGee, Patrick. "Do immigrants take jobs from U.S. workers?" Fort-Worth Star-Telegram, Aug. 11, 2006.
Orrenius, Pia. "U.S. immigration and economic growth: putting policy on hold." Southwest Economy, Federal Reserve Bank of Dallas, Nov./Dec. 2003.
Orrenius, Pia and Genevieve Solomon. "How labor market policies shape immigrants' opportunities." Economic Letter, Federal Reserve Bank of Dallas, July 2006.
Center for Immigration Studies
"The Center for Immigration Studies is an independent, non-partisan, non-profit research organization founded in 1985. It is the nation's only think tank devoted exclusively to research and policy analysis of the economic, social, demographic, fiscal, and other impacts of immigration on the United States."
Migration Policy Institute
"The Migration Policy Institute (MPI) is an independent, nonpartisan, nonprofit think tank in Washington, DC, dedicated to the study of the movement of people worldwide. MPI provides analysis, development, and evaluation of migration and refugee policies at the local, national, and international levels. It aims to meet the rising demand for pragmatic and thoughtful responses to the challenges and opportunities that large-scale migration, whether voluntary or forced, presents to communities and institutions in an increasingly integrated world."
Civil Rights.org Immigration Resources
Clearinghouse for immigration news and information. Takes what might be deemed a "pro-immigration" stance.
Carnegie Endowment for International Peace
Coverage topics include a collection of resources on immigration. See in particular "Research perspectives on migration."
Library of Economics and Liberty
Entry on immigration written by labor economist George Borjas takes a more critical stance toward immigration.
The Promise of Immigration
An exchange between numerous authors in the Boston Review about immigration. See in particular the response by economist Jagdish Bhagwati.
"The Economics of Immigration Policy" [PDF Slides]
David Card, University of California at Berkeley presentation at Supply, Demand and Deadlines Workshop for Journalists, October 16, 2006.
Interview with David Card, The Region, December 2006