You write entries in text files, you can mark them up with whatever HTML you want, and there are a few additional useful formatting commands for including images and bulleted lists. The layout of your page is completely customizable, and it includes an RSS generator. All of this is described in the included README file.
If NitLog doesn't do something you want it to do, it could be because I never thought of it or was too lazy. Please feel free to let me know what you'd like to see. Better yet, please feel doubly free to do some hacking yourself and send me a patch.
--dcoombs
dcoombs (2004/11/17): NitLog is currently available only via AnonymousSubversion, under the project name
nitlog.
apenwarr (2008/09/08): Actually, my latest version is now hosted at GitHub?: http://github.com/apenwarr/nitlog/