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.

rich! @ etiviti

Yuttadhammo

Eduardo

This plugin allows remote access to BuddyPress networks through an XML-RPC API.
A client application is required to connect to this BuddyPress XML-RPC plugin. 
This could be anything from a standalone WordPress plugin to an iPhone or 
Android app.
An Android app designed for use with this plugin is available on Google Play:
https://play.google.com/store/apps/details?id=org.yuttadhammo.buddydroid
For more information on using this plugin, please read the FAQ and About Page.
<h4>Related Links:</h4>
<ul>
<li><a href="https://plugins.svn.wordpress.org/buddypress-xml-rpc-receiver/" title="SVN repository" rel="nofollow ugc">Source code</a></li>
</ul>

BuddyPress XML-RPC Receiver

This plugin allows remote access to BuddyPress networks through an XML-RPC API.

XML-RPC Modernization vs BuddyPress XML-RPC Receiver