Almost all Mac OS X applications has built-in support for pattern colors, via the standard color panel palettes. Norrkross Patterns is a very simple editor to create palettes of pattern colors from images.
Build up your color palette by dragging in images, naming them and then click Add. When done save it to
~/Library/Colors/ (your personal colors directory),
or /Library/Colors/ (shared colors on the computer),
After that the color palette should appear in all applications that use the standard color panel in all applications that use it (eg. TextEdit, Mail).
Norrkross Patterns is free to use and distribute.