Rename it update.zip and move it to your Droid X SD card.
Power off your Droid X.
Hold down the home buttons and power button. When you see the Motorola logo appear, you can let go of the power button.
When you see the Droid with the exclamation mark, press the search key once.
You'll now be in recovery. Choose to install update.zip, and you're on your way!
I used the link that was included in the AndroidCentral post and that did exactly the same thing as this download did...