Google Data API has support for
JSON. For the moment, the JSON output can be used in Blogger Beta, Calendar, and Google Base. As you probably know, JSON is an easy way to obtain data, parse it and use it in your web application. And because JSON uses JavaScript, the output can be used directly in the code.
Examples and details for the implementation can be found in
Google Data APIs Developer's Guide.
Related:
Unofficial JSON API for Google Search
