.htaccess

.htaccess is a very useful way to accomplish things that HTML and CSS can't, however it is very rarely allowed on free-servers. You should check with your system administrator to make sure that .htaccess is allowed/enabled before trying out these tutorials.

Error Pages
Customize your 404 and other error pages.

Private Directories
Password protect your private folders.

Anti-Leech
Stop people from remotely linking to your image files.

Anti-Leech test
See if your .htaccess anti-leech is working here.

Hotlinking
All about leeching files and why it is wrong.