You can obtain discounted tickets through "Beneplace" (United States based only). Their orders are processed via "TicketsAtWork" (who does accept foreign credit card payments). Both sites will add taxes and processing fees at time of purchase. If you live in the United States, you many want to check both sites as they offer different ticket options.
Passcode for each venue is: ibmer
BENEPLACE FOR IBM RETIREES: http://www2.beneplace.com/ibmretirees
TICKETS AT WORK: https://www.ticketsatwork.com/tickets/
Before ordering tickets from either of the above, you may want to compare prices from the Walt Disney site as well (www.disney.com) and/or other websites offering discounts like Triple A, etc.