Available at the Family History Library, and most public and academic libraries.
"Begun as a print product, the Biography and Genealogy Master Index (BGMI) functions very well as a database. It is the largest biographical index available, indexing more than 15 million biographies from 1,700 biographical dictionaries, including new ones as they appear." (Booklist, January 15, 2007)
But it does not include local biographical sources.