Be sure to check the dates on the back of your AP once it is activated. I previously read a couple of people say that they date on the back of their actual AP showed the expiration date as being the day they activated it. Thought that was odd and made a mental note to self to be sure and check my date upon activation.
I presented my voucher for activation at Downtown Disney on the 30th of April. On May 1st, our first day at the parks, I was rejected admittance through the turnstyles because my "pass had expired". The CM showed me the dates on the back - and sure enough, it showed April 30, 2004 as being the expiration date! So much for the mental note I made to myself.
These passes are very flimsy. I carried mine in my pocket during the entire first day - and it wouldn't work on the second day. Had to get another pass. That would be two passes within two days. Why don't they make them out of credit card type material? Or at least advise you to take extra care where you store your AP.
Have fun!