Max Cutler

This plugin brings XML-RPC API enhancements from the WordPress 3.4 release to previous versions 
of WordPress (3.3 and earlier). It also adds new user management methods.
It is derived from Prasath Nadarajah’s GSoC ’11 project to expand WordPress’ web services, 
although the exposed API methods are not compatible (different parameter names/types/orders).
<h4>Methods</h4>
New Methods:
<ul>
<li>wp.newUser – create a new user</li>
<li>wp.editUser – edit user information</li>
<li>wp.deleteUser – delete a specfic user</li>
</ul>
3.5 Methods for pre-3.5 sites:
<ul>
<li>wp.getUser – get information about a specific user</li>
<li>wp.getUsers – retrieve a list of users</li>
<li>wp.getProfile – retrieve information about the requesting user</li>
<li>wp.editProfile – edit the profile of the requesting user</li>
<li>wp.getRevisions – retrieve revisions for a specific post</li>
<li>wp.restoreRevision – restore a post revision</li>
</ul>
3.4 Methods for pre-3.4 sites:
<ul>
<li>wp.newPost – create a new post (of any post type)</li>
<li>wp.editPost – edit a post (of any post type)</li>
<li>wp.deletePost – delete a post (of any post type)</li>
<li>wp.getPost – get a specific post (of any post type)</li>
<li>wp.getPosts – get a list of posts</li>
<li>wp.getPostType – get information about a specific post type</li>
<li>wp.getPostTypes – get a list of registered post types</li>
<li>wp.getTaxonomy – get information about a specific taxonomy</li>
<li>wp.getTaxonomies – get a list of registered taxonomies</li>
<li>wp.newTerm – create a new term in a taxonomy</li>
<li>wp.editTerm – edit a term in a taxonomy</li>
<li>wp.deleteTerm – delete a term in a taxonomy</li>
<li>wp.getTerm – get information about a specific term in a taxonomy</li>
<li>wp.getTerms – get a list of term associated with a taxonomy</li>
</ul>

XML-RPC Modernization

excelent

This plugin updates the WordPress XML-RPC API to leverage the latest features of WordPress and move beyond the historical Blogger/metaWeblog/MT APIs.

tildemark

This plugin will completely disable or deactivate XML-RPC on your WordPress installation. This will prevent any brute force attacks to your website using XML-RPC.
By using the plugin, it will remove your ability to post using XML-RPC protocol, which means no more,
<ul>
<li>post ping backs, </li>
<li>remote post from WordPress mobile app, </li>
<li>remote post from windows live writer, </li>
<li>and other applications that requires XML-RPC.</li>
</ul>

Deactivate XML-RPC on WordPress

This plugin will completely disable or deactivates XML-RPC on your WordPress installation. This will prevent any brute force attacks to your website u …

XML-RPC Modernization vs Deactivate XML-RPC on WordPress