ColorTagz is a fun color palette/theme app, that allows you to create color palettes from images.
Just open an image or drop one from your desktop and pick the colors.
You can copy and paste color and Tagz and save the results.
The file format is provided along with monkey2 (basic like) source code for loading ColorTagz into your own apps.
You can also export the current image with embedded tag or all tagz as images for use on the web, or whatever you want :)