PHP-FileSystem is a web file system navigator/browser. It provides a nice and easy to use interface, that allows visitors to navigate into a directory of your web server. It's easy to setup and fully customisable through a simple templating mecanism. You can create your own template by simply building your index page and filling a single CSS file. This tool comes with a default template as an example for yours.

PHP-FileSystem is definitely a good alternative to complex download website tools when you just want to share some files with the world.