What is it?
This is a plugin to be used with WP-RESTful Plugin for WordPress, it is not a direct WordPress Plugin. This will not work unless you have WP-RESTful installed and active on your WordPress Installation. 
By using this plugin your REST API will be able to return User information and verify user credentials.
Widget
This Plugin also comes with a fully functional Widget that will enable you to login with other blogs as long as they also use this plugin and allow it. User Sessions are virtualized.
Plugin features?
<ul>
<li>Share user information through the API.</li>
<li>Verify Credentials.</li>
<li>Login with external Blogs.</li>
<li>Session Virtualization. </li>
</ul>
Requirements?
You need to have WP-RESTful installed and active for this Plugin to work.
<h3>Additional help</h3>
You can find additional information by visiting this plugin homepage: http://www.joseairosa.com/2010/06/29/wp-restful-wordpress-plugin/
<h3>What’s in the cooking pan?</h3>
If you have any features that you would like to see implemented, please don’t hesitate to tweet me (http://twitter.com/joseairosa) or mail me (me@joseairosa.com) 🙂

WP RESTful Users Plugin

The WP-RESTful User Plugin is a REST API module to be used with WP-RESTful Plugin for WordPress.

What is it?
This is a plugin to be used with WP-RESTful Plugin for WordPress, it is not a direct WordPress Plugin. This will not work unless you have WP-RESTful installed and active on your WordPress Installation. 
By using this plugin your REST API will be able to return Categories information.
Widget
This Plugin also comes with a fully functional Widget that will enable you to list your connected servers Categories.
Plugin features?
<ul>
<li>Share categories information through the API.</li>
</ul>
Requirements?
You need to have WP-RESTful installed and active for this Plugin to work.
<h3>Additional help</h3>
You can find additional information by visiting this plugin homepage: http://www.joseairosa.com/2010/06/29/wp-restful-wordpress-plugin/
<h3>What’s in the cooking pan?</h3>
If you have any features that you would like to see implemented, please don’t hesitate to tweet me (http://twitter.com/joseairosa) or mail me (me@joseairosa.com) 🙂

WP RESTful Categories Plugin

The WP-RESTful Categories Plugin is a REST API module to be used with WP-RESTful Plugin for WordPress.

WP RESTful Users Plugin vs WP RESTful Categories Plugin