I like this tutorial for tables. here (http://www.pagetutor.com/pagetutor/tables/)
Also, as Jon says, the cells often take on the width of the data in them if there are no line breaks. Two tricks I've found very useful are the non breaking space (nbsp;) to enter something in a cell to hold it in place, and also the clear single pixel gif trick. You can also specify horizontal and vertical spacings. It's always just best to view your HTML, especially tables, in different browsers and different screen resolutions.
Now if I had time, I'd do something with that picture above. I think I could just call it from the Mudcat server and add some text decorations...but just use your imaginations!