In the past, biographies were classfied with Dewey Decimal call number 920, and many older biographies are still in the 920's. More recent biographies are arranged in the collection based on the person's area of renown.
Reference books for biography include:
American National Biography REF 920.073 A5126g
Current Biography REF 920.02 C
Scribner Encyclopedia of American Lives REF 920.073 S434j 1998
Scribner Encyclopedia of American Lives: Sports Figures REF 796.0922 S4342m 2002
Black Women in America REF 920.72 B627h 2005
Women in World History REF 920.72 W8724c 1999
Contemporary Authors REF 928.1 C761g
e-books are included in Discover Biographies
People currently in the news like singers and athletes rarely have books written about them yet. Your best bet is to find magazine articles, so try Academic Search Premier or Academic OneFile. For newspaper articles, try Newspaper Source or LexisNexis Academic.