Did you buy your tickets yet? I was wondering that same thing. Hopefully they are good indefinately. Let me know if you have found anything out about that. Thanks!
We bought e - tickets online, they are good for one year exactly.
Side note, we got the two park, unlimited tickets. We can go to Busch gardens (which we were planning) and Sea World unlimited for seven days. $85 pp. I thought it was a great deal - we're staying nearby, so we can go a half a day now and then depending on what WDW is like that day.