Principal FOIA Contacts at Federal Agencies

"The Department of Justice's Office of Information and Privacy (OIP) is the principal contact point within the executive branch for advice and policy guidance on matters pertaining to the administration of the Freedom of Information Act. Experienced FOIA advisers are available to respond to FOIA-related inquiries at (202) 514-3642 (514-FOIA)."

This site also links to the DOJ's FOIA Reference Guide which tells you all you need to know to make a FOIA request.