WinAmp Classic - Skins for the WinAmp media
player
WinAmp Modern - Freeform skins for the WinAmp media
player
Wallpapers - Background image for your desktop
Skins are custom graphical appearances for software (GUI - graphical user interface), and also websites.
It basicly let's you choose a different look of the software/website, but keeping the functionality (usually).
Skins can be used to make a total 'theme' for your computer software, so that everything has the same look and feel.
Some program's you use probably is 'skinnable'.
Like for example Windows Media Player.
Or Mozilla Firefox webbrowser.
Even M$ Windows Vista uses theme's these days.
One of the most popular 'skinnable' program is WinAmp.
It's a media player (music, video). And it's new version also supports freeform skinning.
This means you can give it your own shape and size, and place the buttons where you want them.
Find out more about skinning WinAmp classic
here.
Find out more about skinning WinAmp modern
here.