Some RdfEditingSoftware:
Ontology editing software
- Protege

- Some Protege plugins available here
- OilEd --an editor for DAML+OIL; however, according to this page, DAML+OIL has been superceded by OWL.
- SWOOP: a lightweight ontology browser / editor with a web browser-inspired user interface

- SMORE: Create OWL Markup for HTML Web Pages

CategoryInformationVisualization
CategorySemanticWeb?