Spot Color has been renamed to Hues. It has a bunch of new features and is available on the Mac App Store from my company, Giant Comet. You can get it at http://giantcomet.com/hues. You can read more about the difference between the apps in this blog post.
Spot Color 1.0.2*
Spot Color is a simple application that allows you to use the standard Mac OS X color picker as a stand-alone app. This allows you to quickly grab colors without having to be in an image editing app like Photoshop. Since it uses the built-in color picker, you can utilize the system wide color picker plugins and swatches.
This is most useful when combined with custom color picker plugins like the recently released Developer Color Picker by Wade Cosgrove at Panic or Hex Color Picker by Waffle Software. Both of these extend the built-in color picker and allow you to get the color in hexadecimal and other formats.
Thanks to Curt Kotula for designing the icon and coming up with the name.
Note: the color pickers mentioned above and shown in the screen shot need to be installed separately. Click through to the sites linked above to download and install.