WordPress.org

If you have ever installed a WordPress plugin, then installation will be pretty easy:

1. Download the Exec-PHP plugin archive and extract the files
2. Copy the resulting exec-php directory into /wp-content/plugins/
3. Activate the plugin through the 'Plugins' menu of WordPress
4. Configure blog and user settings if needed

For support and further information about the Exec-PHP plugin see the plugins homepage at http://bluesome.net/post/2005/08/18/50/.