From a recent release:
As of April 1, 2010, the Bibliography of the History of Art (BHA) will be available free of charge on the Getty Web site at http://library.getty.edu/bha. Free Web access to BHA is an advantage not only to all traditional users of the database but also to such potential users as institutions in developing countries and independent scholars worldwide, who until now have been unable to afford access to the BHA.
BHA on the Getty Web site offers both basic and advanced search modules, and can be searched easily by subject, artist, author, article or journal title, and other elements. To search BHA, please visit, http://library.getty.edu/bha. Note that the database search includes both BHA (covering 1990-2007) and the International Bibliography of Art (IBA), covering the years 2008 and part of 2009. The Répertoire de la litterature de l’art (RILA), one of the predecessors of BHA, with records that cover 1975-1989, will be online by May 1.
Use the BHA at: http://library.getty.edu/bha