Disneyland paris uk site are offering 40% off direct bookings if you book before 15th april.
You can book online or by phone - by phone you can pay 10% deposit.
If you want to book by phone its worth using their online booking system to find the dates/deal/hotel you want as it is selected dates and hotels.
When you check the prices online it will say in the description if the 40% discount has been applied.
I have booked for august!! woohoo.
People are also saying it is good to book the halfboard option (I have) because of the poor exchange rate.
Just a an extra note I teamed up my booking with cheap easy jet flights.