gCLUTO - Graphical Clustering Toolkit
gCLUTO is a cross-platform graphical application for clustering low- and high-dimensional datasets and for analyzing the characteristics of the various clusters. gCLUTO is build on-top of the CLUTO clustering library.
gCLUTO provides tools for visualizing the resulting clustering solutions using tree, matrix, and an OpenGL-based mountain visualization.
Here are some screenshots of gCLUTO's various screens and visualizations.