WordPress Tip: When you Forget your WordPress Username and Password
In working with clients on WordPress projects, I routinely run across people who forget their WordPress username and password. Fortunately, if you still remember the FTP username and password, just upload this "emergency.php" script from Yoast to your root directory, go to http://yoursite.com/emergency.php, and voila, you can change your WordPress username and password. You may need to download the wp-config.php file to grab the database password, but that's it.