DC-dot - web-based Dublin Core generator and editor from the UK Office for Library and Information Networking (UKOLN)
Dublin Core Assistant (DC-Assist) - help utility for metadata applications and is intended to complement the help pages embedded within existing software
XML Spy - centered around a validating XML editor that provides four views on documents: Enhanced Grid View for structured editing, Database/Table view that shows repeated elements in a tabular fashion, a Text View with syntax-coloring for low-level work, and integrated Browser View that supports both CSS and XSL style-sheets