NETTUTS.com has a list of fifty WordPress tutorials you can use on your installation to do things like:

• Multiple Wordpress Installations Using a Single Database
• Wordpress Theme Hacks
• Turning a Web Template Into a Wordpress Theme
• Rounded Corner Tab Menus
• Customizing Widgets Using CSS
• Wordpress Categories in a Horizontal Drop-down Menu
• Enabling HTTPS for Wordpress.com Blogs Screencast

Check out the full post for even more WordPress goodness.