Open source 'Visio' alternatives
Available for: linux & unix
Kivio is part of the KOffice open source office suite. For flowcharting, network diagrams and all other graphing need Kivio solves them with an easy to user interface. As part of the KOffice office...
Available for: windows, mac, linux, unix & java
ArgoUML is a great UML (Unified Modeling Language) tool. Written in Java and using Java Web Start makes it easy to work with (install) and use on any platform.
Available for: windows
StarUML is a great open source UML application. Supporting UML 2.0 and MDA (Model Driven Architecture) StarUML let's you work with all related diagrams.
Available for: windows, linux & unix
Dia is designed to be much like the commercial Windows program 'Visio'. It can be used to draw many different kinds of diagrams.
Available for: windows, mac, linux & unix
As part of the OpenOffice - Draw takes care of all of you drawing and graphing needs. With ease connectors can be added between objects making network, flow and even organization charting easy.