Carto is a small editor for Google Sitemap files.
It allows you to create, change, batch edit, and search page settings for a sitemap file.
It imports (and of course) exports sitemal.xml files.
You can also drag-n-drop URLs from a web browser, or fetch the current modification date for an URL by querying the web server.
It also handles redirects and updates the page URL as needed.
Carto source code is also an example for a simple Core Data application, with an array controller customized for drag-n-drop, and a short example of Web Kit / Foundation URL loading code.