This is for programmers only: Genealogy web site Geni.com has released an API that allows Geni users to develop third-party tools and applications that can interact with the breadth of data that the community has contributed for the past three years. If the data is public, no API key is required to access it. Only private data requires authentication to access. Data is returned in JSON or XML format.
The Geni developers have created a sample Ruby application for reference.
You can read more about the new Geni API at http://www.geni.com/blog/introducing-the-geni-api/