Roch, NY Cloning in SW

Before I saw Ep.2 I assumed that cloning would be a new thing to star wars universe in this film, but it obviously is not. It is known that the Kimonions or what ever they are called, do this as there main business. It seems as if they have been doing it for a long long time. So the questions are how long have there been clones in the SW universe? Who else has used them? And for what? I would thing think that they would be programed and used to replace any droids, not just Battle droids. So where are the rest of the clones? Does anyone have a clue to any of this?