New Zealand @digitalnz API
http://www.digitalnz.org/developers
Museum Victoria, Australia, API
http://museumvictoria.com.au/collections/help/api
Europeana API Email katy@wearecaper.com for API key
API technical documentation can be found at http://europeanalabs.eu/wiki/EuropeanaOpenSearchAPI
General API-information and a gallery of API-implementations and prototypes can be found at http://www.version1.europeana.eu/web/api
Smithsonian
http://collections.si.edu/search/
Adlib API
http://api.adlibsoft.com/site/