When I have purchased my tickets online, I received an email with a code that I then used at one of the parks to get the actual tickets. Note that I did NOT have to stand in the normal ticket purchasing lines to do this. You can go to a separate "Will Call" window which normally should be very quick.

I do believe they may even have a kiosk or two that you can use to get your tickets from as well. You just type in your confirmation number and provide them the credit card used to pay for the tickets and it will give you your tickets.