The National Park Service's Archeology Program provides a wealth of information for both archaeological professionals and the interested public at http://www.nps.gov/history/archeology/index.htm.
Below are some additional links within the National Park Service that you may find useful:
The Advisory Council on Historic Preservation contains useful Section 106 archaeology guidance for archaeological professionals.
The Bureau of Indian Affairs website provides information about the history, preservation, and protection of Native American sites.
The United States Forest Service's Passport in Time, a volunteer archaeology and historic preservation program.
The U.S. Fish and Wildlife Service's Historic Preservation Program contains useful guidance and information about cultural resource management and archaeological sites.
Introduction || Historic Preservation