Index: wp-includes/class-wp-xmlrpc-server.php
===================================================================
--- wp-includes/class-wp-xmlrpc-server.php	(revision 19632)
+++ wp-includes/class-wp-xmlrpc-server.php	(working copy)
@@ -64,6 +64,7 @@
 			'wp.getMediaItem'		=> 'this:wp_getMediaItem',
 			'wp.getMediaLibrary'	=> 'this:wp_getMediaLibrary',
 			'wp.getPostFormats'     => 'this:wp_getPostFormats',
+			'wp.editTerm'			=> 'this:wp_editTerm',
 
 			// Blogger API
 			'blogger.getUsersBlogs' => 'this:blogger_getUsersBlogs',
@@ -1702,6 +1703,101 @@
 		return $formats;
 	}
 
+	/**
+	 * Edit a term
+	 *
+	 * @uses wp_update_term()
+	 * @param array $args Method parameters. Contains:
+	 *  - int     $blog_id
+	 *  - string  $username
+	 *  - string  $password
+	 *  - int     $term_id
+	 *  - array   $content_struct.
+	 *      The $content_struct must contain:
+	 *      - 'taxonomy'
+	 *      Also, it can optionally contain:
+	 *      - 'name'
+	 *      - 'parent'
+	 *      - 'description'
+	 *      - 'slug'
+	 *  - boolean $send_mail optional. Defaults to false
+	 * @return int term_id
+	 */
+	function wp_editTerm( $args ) {
+		$this->escape( $args );
+
+		$blog_id            = (int) $args[0];
+		$username           = $args[1];
+		$password           = $args[2];
+		$term_id            = (int) $args[3];
+		$content_struct     = $args[4];
+
+		if ( ! $user = $this->login( $username, $password ) )
+			return $this->error;
+
+		do_action( 'xmlrpc_call', 'wp.editTerm' );
+
+		if ( ! taxonomy_exists( $content_struct['taxonomy'] ) )
+			return new IXR_Error( 403, __( 'Invalid taxonomy.' ) );
+
+		$taxonomy = get_taxonomy( $content_struct['taxonomy'] );
+
+		if( ! current_user_can( $taxonomy->cap->edit_terms ) )
+			return new IXR_Error( 401, __( 'You are not allowed to edit terms in this taxonomy.' ) );
+
+		$taxonomy = (array) $taxonomy;
+
+		// hold the data of the term
+		$term_data = array();
+
+		$term = get_term( $term_id , $content_struct['taxonomy'] );
+
+		if ( is_wp_error( $term ) )
+			return new IXR_Error( 500, $term->get_error_message() );
+
+		if ( ! $term )
+			return new IXR_Error( 404, __('Invalid term ID.') );
+
+		if( isset ( $content_struct['name'] ) ) {
+			$term_data['name'] = trim( $content_struct['name'] );
+
+			if( empty ( $term_data['name'] ) )
+				return new IXR_Error( 403, __( 'The term name cannot be empty.' ) );
+		}
+
+		if( isset ( $content_struct['parent'] ) ) {
+			if( ! $taxonomy['hierarchical'] )
+				return new IXR_Error( 403, __( 'This taxonomy is not hierarchical.' ) );
+
+			$parent_term_id = (int) $content_struct['parent'];
+			$parent_term = get_term( $parent_term_id , $taxonomy['name'] );
+
+			if ( is_wp_error( $parent_term) )
+				return new IXR_Error( 500, $term->get_error_message() );
+
+			if ( ! $parent_term )
+				return new IXR_Error( 403, __('Invalid parent term ID.') );
+
+			$term_data['parent'] = $content_struct['parent'];
+		}
+
+		if( isset ( $content_struct['description'] ) )
+			$term_data['description'] = $content_struct['description'];
+
+		if( isset ( $content_struct['slug'] ) )
+			$term_data['slug'] = $content_struct['slug'];
+
+		$term = wp_update_term( $term_id , $taxonomy['name'] , $term_data );
+
+		if ( is_wp_error( $term ) )
+			return new IXR_Error( 500, $term->get_error_message() );
+
+		if ( ! $term )
+			return new IXR_Error( 500, __('Sorry, editing the term failed.') );
+
+		return $term['term_id'];
+	}
+
 	/* Blogger API functions.
 	 * specs on http://plant.blogger.com/api and http://groups.yahoo.com/group/bloggerDev/
 	 */