For one of my sites, I want to create a developer API so that other people can leverage of what we build to quickly put together their own solutions (I guess something like Google Maps is a good parallel example). We'd like to control who uses it since we have data providers who would like to know when we pass data on to someone else.
What would you recommend that I read? It's fine if it's a book (doesn't need to be only online articles though those would give me a good start also). [needless to say, Rails would be my preferred choice].