Webdav is a functionality of the web server (probably apache for you), not so much of the operating system. You'll need to make sure that the apache webdav module is loaded and enabled, decide what part of your filesystem to make accessible via webdav, then add some things to the apache configuration files (/etc/httpd/conf/httpd.conf) to configure webdav, and restart apache.
There are detailed instructions here:
http://www.twilight-systems.com/flac...ache2-rh9.html
