It’s time again to present a nice tool which is free and useable. Maybe you’ve already heard of DIA. It’s a freeware and open source diagramming software. Well I would like to say „Visio clone“ but it’s not as powerful as Visio and doesn’t exactly look as nice. But hey, it’s free and it covers the main functionality.
You can import your own shapes, which should be in a XML or SVG format. DIA can be scrippted using the Python programming language.
The diagrams can be saved or exported to various formats like: XML, PNG, EPS, SVG, WMF or JPEG. You can find more information or download the latest version at the official homepage.