When you get right down to it - most web games are scripts that manipulate data in a database and present the results and controls in a browser. So one of the fundamental pieces of any webgame is it's database. fabForce has made DBDesigner4 - a database design application that is pleasing to look at, easy to use, available for windows and linux and open source (aka free). I've been using it for some time now and I'm very impressed.