Customize.org
Provides theme details, reviews, and downloads. Submit and review skins, post comments in the forum, and vote in polls with the free membership.
Kephra Design
Themes, wallpapers, screensavers, and link to other resource sites. Offers, web design and consultation.
Ohussain Themes
All themes are OTS compliant and have been updated to work with the latest builds.
OrangeBoxLS
Themes as well as information on theming and other useful information aimed at the newbie LS user. Also contains links to sites within both the LS community and the desktop customizing community.
WinCustomize Skins and Visual Styles
Library with over 150 themes with reviews and author contact information.