Astonshell
Aston - fast, stable, secure and reliable desktop replacement. beautiful themes on your desktop. virtual desktop manager for windows
http://www.astonshell.com/
WinAmp skins
Find and download skins for your winamp media player. customize the way winamp looks with skins.
http://www.winamp.com/skins/
Skinbase
Skinbase.org - wallpapers and skinning portal with support for a many skinnable applications
http://www.skinbase.org/
Pinkelotje MSN
Download, msn, skins, msnskins, msn messenger skins
http://www.pinkelotje.nl/msn.html
Lots of skins
Lotsofskins.com - skins and skins to customize your desktop!
http://www.lotsofskins.com/
Skinz.org
Free winamp and icq skins made made by users for the skins community to share free
http://www.skinz.org/
Win-Amp skins
Win-Amp skins
http://www.winamp-skins.com/
Theme Xp
The #1 themes site xp themes, xp styles, xp logins, vista themes, screensavers, wallpaper, desktop themes, windows themes
http://www.themexp.org/
Stardock
Stardock, your competitive edge in corporate solutions, entertainment and consumer software for windows xp/vista. themes, skins, icons, desktop enhancements and strategy games!
http://www.stardock.com/
Wincustomize
Download vista dreamscenes, vista themes, xp skins & visual styles and desktop themes for desktopx, windowblinds, objectdock, google and vista sidebar gadgets, sysmetrix, winamp, windows desktop themes and more!
http://www.wincustomize.org/