I'm setting up a new website, and am trying to find a good way of putting up a menu. I think the think Lissa uses at the top of the screen, that looks like tabs on file folders, is really neat. How do you do this?

it is just a bunch of linked images. follow her tutorials and you should easily be able to do the same.
for some different types of navigation, perhaps try here...
http://www.dynamicdrive.com

good luck!