• Objects: Objects begin and end with curly braces ({}).
• Object Members:  Members consist of strings and values, separated by colon (:). Members are separated by commas.
• Arrays:  Arrays begin and end with braces and contain values. Values are separated by commas.
• Values: A value can be a string, a number, an object, an array, or the literals true, false or null.
• Strings: Strings are surrounded by double quotes and contain Unicode characters or common backslash escapes.

Developer.com
Contains resources, tools, articles, discussion areas, and events of interest to Internet/intranet developers. Directories include: ActiveX, Java, JavaBeans, JavaScript, Microsoft and .NET, open source and VRML.

JSON for Ajax Web services
JSON is a subset to JavaScript, the de facto programming language used in all browsers. By structuring a data payload as a JSON response, you are effectively bypassing the need to parse an XML document in a browser — typically done via JavaScript of course — to get to the actual data.

Speeding Up AJAX with JSON
The XMLHttpRequest object analyzes the MIME type of the data coming back from the Web server by looking at the Content-type header that precedes the data.

Tutorial: User-Defined Objects
This tutorial describes JSON, a cross language data interchange format.