ERD Webapp Tool
Today I found myself in need of a lightweight ERD tool. I was planning a small relational database and I was on a windows machine. I didn't want a heavy-handed tool like Visio or DBArtisan so I did some Google-foo and found WWW SQL Designer. It's a javascript based web app for making small ERD's. Check out this awesome live demo. It's easy and the results look nice enough. You can also save the entire design as XML and take it with you. I dare say, this might even be easier than using OmniGraffle.