All-American Girls Professional Baseball League
http://www.aagpbl.org/index.cfm

Baseball: A Film by Ken Burns
http://www.pbs.org/kenburns/baseball/

Baseball as America
http://www.baseballasamerica.org/

Baseball Fun Facts
http://www.factmonster.com/ipka/A0771577.html

Blackbaseball.com: Negro Baseball Leagues
http://www.blackbaseball.com/

Negro Leagues Baseball Museum
http://www.nlbm.com/s/index.cfm

National Baseball Hall of Fame and Museum
http://www.baseballhalloffame.org/

Science of Baseball
http://www.exploratorium.edu/baseball/