Dostoevsky.com

Postnuke Themes at SourceForge
Provides a theme pack for PostNuke .64 and two new themes for PostNuke .71 [Open Source, GPL].
sourceforge.net/

Mrs. Ayers' Kinder Themes
A small collection of thematic units for Kindergarten that can be adapted for other grades as well.
www.angelfire.com/

Fermilab Themes for KDE
These themes were made for Linux's KDE Desktop. Several themes available, that includes nature, landscape and mechanical.
home.fnal.gov/

Cats Desktop Themes
Free cats screensavers, desktop wallpaper and themes for the computer enjoyment.
www.chocolatecats.com/

Freshmeat's Window Maker Themes
Themes for Window Maker. Formerly wm.themes.org until themes.org merged with Freshmeat.
themes.freshmeat.net/

MozDev Themes
A large collection of themes, including icon packs and splash screens.
themes.mozdev.org/

The Extension Mirror - Themes
An unofficial list of themes available for Mozilla Firefox.
www.extensionsmirror.nl/

Themes.org
Site provides the Linux and UNIX community with the highest quality repository of graphics, and the central resource for themes. No matter what your personal tastes, or current mood is you will find a theme.
themes.freshmeat.net/

Extreme Themes
Variety of themes and screensavers for download, and Web and graphic design.
www.extremethemes.net/

PC Themes
Custom desktop themes and screen savers for advertising and marketing using wallpaper, sounds, icons, cursors, mouse pointers, skins, web views, startup and shutdown screens, font and color settings.
www.pcthemes.com/