ColorSpace have set themselves the task to create a place where you can find matching colors, generate nice color palettes and learn more about color conversions and meaning. Sometimes it is hard to find inspiration for a good color scheme or you do not have the time to experiment until you find matching colors.
Their collection of tools has just been released and is currently in beta. At the moment, you can generate color palettes or create nice CSS gradients from colors of your choice.
A very useful free color wheel and color palette generator for designers and developers. You can also upload an image to get colors from it.
Dribbble Color is a wonderful tool that allows you to display all dribbble shots, based on certain colors.
Gradient by ShopFactory is a great tool for finding wonderful gradients, to use in your next project. It allows you to control the gradients based on different settings.