This zip file contains a php web application to give a GUI interface to the Rackspace Cloud DNS API. It requires Linux, PHP, and curl be installed on the server it runs on. Just unzip the files and upload them to a web server, then hit them with your browser to get started.
I have built this DNS interface mostly using these two links:
Once you log in, the application gives you the chance to designate a subaccount number. This is useful if using the Clients feature of the Cloud Sites service.