This is the most enormous plot hole in the entire prequel trilogy. Who ordered this clone army? And why were the Jedi so quick to use it before they had ascertained its origin?
Most probably, Sifo-Dyas was either a disguised Darth Sidious (Sifo-Dyas... Si..dyas?) or a disguised Count Dooku. Ep. II hinted that someone had access to the Jedi files and did bad things with the info (this was probably Dooku). But this leap presupposes that one of them was able to see that far into the future, that that the Jedi were a bunch of foolish idiots, and then impersonate a dead Jedi master and make the order (on credit, too!).
At best, I'm counting on EU (expanded universe) authors to step up and fill this plot hole with something satisfying and interesting. Back in the early nineties Timothy Zahn came out with a fantastic set of sequels to the original trilogy. It goes without saying that some of the most creative minds working in the Star Wars universe are out there writing books and comics, and they've got a whole new block of time and action to play with from the prequel movies. Star Wars is not so easily destroyed, even by the likes of George Lucas. If you haven't seen any of the Jedi Council comics that came out a few years ago (which chronicle the adventures of Mace Windu, Ki-Adi-Mundi... and Yoda's girlfriend, Yaddle?!), I recommend them.
