UML Software
Get flash to fully experience Pearltrees
Modelio OSS Community Edition
Papyrus
ArgoUML
Bouml
The Model Development Tools (MDT) project focuses on big "M" modeling within the Modeling project. Its purpose is twofold: To provide an implementation of industry standard metamodels.
Modeling - MDT - Home
The Unified Modeling Language (UML) has quickly become the de-facto standard for building Object-Oriented software.
UML Tutorial - UML Unified Modelling Language - Sparx Systems
Enterprise Architect (Visual Modeling Platform)
Sparx Systems Enterprise Architect is a visual modeling and design tool based on the OMG UML . The platform supports: the design and construction of software systems; modeling business processes; and modeling industry based domains. It is used by businesses and organizations to not only model the architecture of their systems, but to process the implementation of these models across the full application development life-cycle.
MetaCASE tool