WDT is a suite of many different tools for web developers.
As said, it has many tools for all tastes.
Not all of them are useful to me but they might be to you... ;-)
For instance, I find interesting how quickly/easily you can produce the CSS code for buttons, layouts or simple text formatting. Very useful if you are not too experienced with CSS (Or maybe you are a WEB developer and you don't want to get too into design stuff).
Image manipulation. Automatic creation of rounded or squared images, resizing and compressing.
It's a nice tool. Unique downside for me is that it seemed to be running a bit slow.
Next step? Go on and give it a try. Under Ubuntu (I tried it with Lucid) you can add the repository with:
sudo add-apt-repository ppa:petrakis/wdt-main
and then you will find the package "wdt" in your repository.