This topic has been brought up a few times so you should be able to find info in the history file. But i can say that if you get references checked it is a good sign but does not mean you are in. Some guys have waited more than 12 months after reference checks for a start. I also know guys you have got the "the thanks but no thanks" after their reference checks. Some guys have been asked back in to complete sections of the process again that were in your position, even guys who have had criminal checks and mouth x-rays have then been asked to re do sections. So basically don't count on anything until you receive the phone call for the start date.
Anyway, good luck!