UML Unified Modeling Language Tools Directory: use cases, class diagram, sequence diagram, object diagram
Unified Modeling Language (UML) Resources
UML Resource Page of the Object Management Group
Unified Modeling Language in Wikipedia
List of Unified Modeling Language tools in Wikipedia
Software Development Articles Directory - UML
Software Development Tools - UML Section
UML Planet - UML News Aggregator
Article: Understanding the Unified Modeling Language (UML)