http://en.wikipedia.org/wiki/Raisins
Raisin varieties depend on the type of grape that is used. The seedless varieties include Thompsons, Flames, and Sultana. Raisins are typically sun-dried, but may also be "water-dipped", or dehydrated. "Golden raisins" are treated with Sulfur Dioxide (SO2) to give them their characteristic color. A particular variety of seedless grape, the Black Corinth, is also sun dried to produce Zante currants, mini raisins that are much darker in colour and have a tart, tangy flavour.
http://en.wikipedia.org/wiki/Sultana_%28grape% 29
The sultana is a type of white, seedless grape of Turkish or Persian origin, as well as a type of raisin made from it; such sultana raisins are often called simply sultanas or sultanis. They are commonly used in South Asian cooking, where they are called Kishmish. These are typically larger than the currants made from Zante grapes but smaller than 'normal' raisins, and are noted for their sweetness and golden colour.