API

Successful API strategy - http://gigaom.com/2011/03/19/the-building-blocks-for-a-successful-api-strategy/
XML vs JSON - http://blog.apigee.com/detail/why_xml_wont_die_xml_vs._json_for_your_api/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+ApigeeBlog+%28Apigee+Blog%29
REST - http://blog.apigee.com/taglist/REST
REST for SQL developers - http://blog.apigee.com/detail/rest_api_design_for_sql_programmers/ (easy to understand REST)