Sometimes you need to link to something other than a WordPress page in your navigation menu. Perhaps you’ve built a photo gallery in ZenPhoto. How do you get it into your menu without hand-coding all your links?
The Page Links To plugin allows you to do just that. Install the plugin, then create a blank post or page with the title of your desired menu item. Scroll down to the Page Links To section of the edit screen and enter the URL of your external page.