In the past few years, JSON, or JavaScript Object Notation has seemed to overtake XML and other data encoding methods on the web. [...] I've also seen numerous examples of developers who create their own sort of JSON encoder rather than either using json_encode or using Zend_Json. What inevitably comes back to bite them is when the data they are encoding contains a special character like quotes, colons, curly brackets, etc.

He demonstrates how the Zend_Json component helps to alleviate some of the worries with built-in features that handle everything from basic encoding/decoding, printing out results in a "pretty" way and a handy way to include executable Javascript (once it's evaled on the other side) in your payload. He finishes the tutorial off with a mention of a very handy method that will please those already having to work with XML - the fromXML() method that automagically converts the data over to JSON for you.