Automatically protects email address in posts, pages, and comments by converting them into safe alternatives (such as an images or obfuscated text) to
Download "emailprotect.zip" and unzip it.
Upload the entire plugin folder to wp-content/plugins/ and activate from the Plugin administrative menu.
Before the plugin will work you must enter your settings under "Email Protect" in the "Settings" menu (also called "options" in pre-2.5 WordPress versions)
Use the automatic upgrade feature. Otherwise download a fresh copy and simply replace your current one.