Ancestry.com
http://www.ancestry.com/

National government

Census Bureau-Genealogy:
https://www.census.gov/topics/population/genealogy.html

National Archives:
http://www.archives.gov/research/alic/reference/genealogy.html

National Archives-Genealogy:
http://www.archives.gov/research/genealogy/index.html

Oklahoma Government

Ok.gov:
http://www.travelok.com/genealogy

Encyclopedia of Oklahoma:
http://digital.library.okstate.edu/encyclopedia/

Oklahoma Historical Society:
http://www.okhistory.org/

SWOSU Digital Commons
Search the names of relatives who have attended SWOSU.  This database covers SWOSU history back to the beginning.
http://dc.swosu.edu/