First of all sorry for my bad English.
I work for a Spanish enterprise called Clay Formación Internacional (http://www.clayformacion.com/clayweb/home.html) and I have created a backoffice tool (it does some basic actions like manage users, courses, roles, logs, grades, etc. in a simple way) to test Moodle 2.0 web services. This tool is part of my diploma project and it was created to find the needs that the web services layer could have, because this enterprise collaborate with DFWikiLABS, and I work in the Moodle web services project (http://potato.lsi.upc.edu/projects/moodlewebservices).
This tool was created to test the connection with Moodle and find the problems that could appear when creating a client. For this reason it only works with a special Moodle 2.0 version that has some functions added to the external.php files (The Moodle version is from August). These functions added solve some of the problems that were found, such as retrieve all the courses in the platform, all the users in a course and stuff.
It works too with a Moodle 1.9 that uses the same web services but backported to this version. It can connect with Moodle using XML-RPC and SOAp protocols, but have some problems when connecting via REST.
In addition to this, it was added a java applet that connect with Moodle via XML-RPC. This applet is part of a visualization tool (created by Diego Alonso Gómez) which is still a beta, but proves that a java tool can connect via web services with Moodle.
I share it just in case it could be useful for the web services development, and if somebody is interested in it I will update the code of the tool and the two Moodles necessaries to test it (Moodle 2.0 and Moodle 1.9).
The next step is to connect with new Moodle versions, due to there have been many changes in the way to connect and also it's necessary to add some functions to the externallib.php files for it to work.
Finally, there is an image of the tool attached with the post.