Changing MPlayer Skins
Changing MPlayer skins is a simple process. Find the skin you like. Have a look at MPlayer skins or checkout Freshmeat skin section.
Download it. Extract and dump it in the skins directory, normally .mplayer/skins/.
Restart mplayer, right click on GUI and select skin browser from drop-down menu.
Select skin and click OK.
Restart MPlayer GUI, and enjoy your new skin.
Thats about it.