Gliffy is a web based diagramming tool similar to Microsoft Visio. And it’s free. This is something that OpenOffice does not yet have included in it’s suite. To be honest, if OpenOffice would get a Visio like program included into it’s suite you’d probably see some more organizations move to it. A lot of companies still require Visio to chart out workflow, code flow, and many other things.

Gliffy can fill in the gap until we see something like this in OpenOffice.