Cyanogen has recently added a new theme manager to Cyanogenmod which allows users to easily customize their own theme (like font, sounds, icons, wallpapers etc.) but now you can purchase these themes from the Cyanogen Theme Showcase app which will act as a store for themes, styles, icons, wallpapers, lock wallpapers, fonts, boot animations and sound packs.
The store will make it easier for users to download and also easier for developers to generate revenue from their work hopefully encouraging them to create better themes and products. Developers can head over here to get their own theme or icons included into the app. The app is currently compatible with only a small amount of devices.