As it turns out, with a quick trip to Google, I am not the only person who has had this question. There are many, many articles/posts dedicated to this very subject, and really the only difference, as one of my kind, yet anonymous blog readers pointed out is the color of the grape.
Let me, or actually, let the good folks at Wikipedia explain in their "disambiguation":
"Raisin" is the general term for any dried grape.
In the United Kingdom, Ireland, Australia, New Zealand, and Canada (translate: everywhere in the English speaking world (just about)) the word "raisin" in reserved for dried, large dark grapes, with "sultana" being a dried, large white grape. Furthermore, a "currant" everywhere is a small, dried Black Corinth grape.
Raisin= dark grape
Sultana= white grape
Currant= Black Corinth grape
In the United States, we simply have Raisins (dark), and Golden Raisins (as their name implies, white). Although, look at the bags below. Annoyingly, they both picture green grapes. *Sigh*
And to add further fuel to the fire, we Americans also have these:
|That's right Baby, Craisins!|
Information on the Mighty Grape Family taken from: