Ringworm is just a fungus. The same fungus that causes Athletes Foot in people (though you can get it elsewhere, in which case it is also ringworm LOL). It has nothing whatsoever to do with the colour of the dog, but yes it is contagious to people.
You're far from guaranteed to get it though. If you do, however, you can simply hot-foot it down to your pharmacy and pick up some lamisil cream. That will take care of ringworm in as little as one application. You can probably use the same thing on the dog, btw.