The jQuery Form Plugin allows you to easily and unobtrusively upgrade HTML forms to use AJAX. The main methods, ajaxForm and ajaxSubmit, gather information from the form element to determine how to manage the submit process. Both of these methods support numerous options which allows you to have full control over how the data is submitted.
This is a jQuery plugin for converting data from XML to JSON format. However its real power lies in its ability to also remap data to a different structure. This can be useful when you have a plugin or application that requires JSON data, but the data is coming from an XML feed that you don't have structural control over. Data is remapped to the structure you need.
jQuery Gantt Chart is a simple chart that implements gantt functionality as a jQuery plugin. Plugin uses AJAX to retrive JSON data and render them as Gantt chart with many features such as zooming or paging.
XML to JSON Plugin (jQuery.xml2json) is a script you can use to convert simple XML into a JSON object.
jTwitter jQuery Twitter API Plugin provides you with an easy Twitter API to access Twitter user information by twitter username.