ForeUI was available as a giveaway on May 3, 2009!
ForeUI is an easy-to-use screen mockup tool which can rapidly create the UI prototypes of your applications. It provides many common UI elements and you can build your mockup with just drag and drop. Various UI themes are available for mockups; you can perform the UI prototyping with Wireframe, Windows XP or Mac OS X UI theme. Also you can turn on the rumple effect to make your prototype more like a "Design on Paper".
EaSynth Look And Feel Designer it is a tool to develop Java look and feel.