Hi Tom,
For future reference, we have special forum for skinning questions.
The way to know what css classes are on the page is to view the source of the rendered html.
Easiest way is to base your skin on an existing skin as these generally have most of the classes and you can just modify them refresh the page and see your work, but viewing the source can help you find out what class is of interest.
All the documentation I've done so far on skinning starts here:
http://www.mojoportal.com/creatingskins.aspx
You will be well served to get a good book on css and read it. Particlarly learn about css selectors (a css class is one kind of selector but not the only kind).
Next release is probably a few weeks away.
Best,
Joe