“NiLuJe” has released a Kindle 3 compatible font hack today. So in addition to changing the screen-saver images, you can now also change to some different typefaces if you would like. See the MobileRead Wiki instructions for installing and using this hack. As in all such cases, you are solely responsible for modifying your Kindle in this way. It is not an approved Amazon update. Here are the Zip files (separate versions for Kindle 2 and for Kindle 3):
For samples of many of the available fonts, see my font samples page. I’m a Georgia2 fan (K2 screenshot):
Updated links to 3.9 version.