Verizon has announced that it will start rolling out the Android 2.3 update for Droid X from tomorrow i.e. May 27. Update will be available over the air and is expected to take around 20-30 minutes in downloading [size 112 MB].
To manually initiate the update, you can Menu Key > tap Settings > About phone > System updates > Download or you will be notified that a system update is available on your device. Tap Download, then Install now.
You can check the full update changelog here.