There are lots of free fonts available on the web, but it can take forever to ferret out the really good ones. Here's a nice collection of typefaces in a variety of styles, free to download (but check the licenses, as some do have limitations or restrictions): fonts, design

This is pretty awesome:
DC Comics editor E. Nelson Bridwell once put together a Kryptonian alphabet, based on the random squiggles that had appeared in the comics. Now it's been turned into a font:

http://kryptonian.info/bridwell/about.html