Colour Palettes are one of the more arty ways to look at colour in images. They can be created yourself with colours you want to fit together, you can download ready made colour palettes or they can be created by analysing and image and using the colours contained in it. The whole idea is to use colours that work together to produce a particular effect, which can be applied to other images. This is a powerful way of colour toning an image.
A colour map is a colour palette created from the the main colours in an image. This is normally done automatically using a program like Adobe Colour Themes or the NBP ColourmapX panel in Photoshop. This colour palette can then be saved and used again to apply the same look to another image.
NBP ColourmapX is a Photoshop panel which can do this from within Photoshop. See also the Fstoppers review of this.
Adobe Colour Themes involves several steps and needs to go onto the Adobe Colour website.