I remember back in 2006/07 I found a very simple to use ER diagramming tool implemented in Java. It was configurable with XML, and could either backward engineer from an existing database, or forward engineer from a diagram into a database. It allowed the diagrams to be exported as an image if I recall. It was a nifty little piece of shareware, and I was trying to convince my employer to pay for a license.
Does anybody recall what I might be thinking of? I need a very simple tool I can use to whip up some ERD's with by tomorrow. So if not the tool that I cannot recall, any other recommendations.