I've seen a lot of times the pronoun them used like an article. For example, in the title of the Delta Rhythm Boys Them bones, or in the first sentence of "Money for nothing":
Now look at them yo-yo's, that's the way you do it.
I know that it's not "proper English" (i.e., not something you'll use in a serious writing), but I'd like to know when it's commonly used, and why. Is there any difference between using it and using the?