This Craft plugin acts as a wrapper for the Redactor Font Color plugin created by Imperavi, which allows setting text and background colors. It has been slightly modified from Imperavi's original version to work in the Craft CMS control panel.
Download the plugin and copy the "redactorcolors" folder into your craft plugins folder. Then go into the Craft CMS control panel and go to Settings > Plugins to install it. Once that is done, you will need to configure your redactor settings files to include the plugin. Those are located in "craft/config/redactor/". For any of the WYSIWYG types that you want to add this plugin to, add "fontcolor" to the plugins list like so:
{
buttons: ['html','formatting','bold','italic','link','image'],
plugins: ['fullscreen', 'fontcolor'],
formattingTags: ['p', 'blockquote', 'pre', 'h1', 'h2', 'h3', 'h4'],
observeLinks: true,
toolbarFixedBox: true
}
If you'd like to customize the colors available, those are defined in "/redactorcolors/resources/fontcolor.js"
Note: You will need to make sure your fields have "Clean up HTML" disabled or your color styles will get stripped out on save.