You will get an online account at dvcmemberDOTcom where you can see a listing of perks and discounts- also you will get a booklet called 'portable perks' at check-in showing all the current perks. (I think I got a portable perks booklet with new member pack that they send out (It is the box with the treasure chest looking box and the tote bag and the closing documents)
As the perks change they will put that info in the magazine they send out or the email newsletter. And you can always check online.