This probably won't be updated much in the future. Lewis from FM-View updated it for his personal use, but shared it in case others want to use it in the meantime. Thanks to Jack for helping with panels.
Hopefully SI will release an official dark skin with the final release of the game.
Released: 18 October 2013
Updated: 26 October 2013
Step 1Download the skin and extract the file (using either 7-Zip for Windows or The Unarchiver for Mac).
Step 2Move the two extracted folders "fm2013fmv dark" and "fm2013fmv dark-widgets" into your skins folder:
Win Vista/7/8: C:\Users\<username>\Documents\Sports Interactive\Football Manager 2014\skins
Win XP: C:\Documents and Settings\<username>\My Documents\Sports Interactive\Football Manager 2014\skins
Mac OS X: /Users/<username>/Documents/Sports Interactive/Football Manager 2014/skins
Create the folder "skins" if it doesn't exist.
Step 3Start the game and go to Preferences screen and Interface tab.
You should see "FM 2014 Dark" as option in the skin drop down of the Overview box.
Hit the Confirm button.
Please note this skin is provided as is. It has nothing to do with Sports Interactive or SEGA and won't be supported by them.