Walt Disney World has added free wifi to their parks and resorts, which is a great benefit, I can remember complaining about overpriced wired internet a year ago. But, I want to recommend that you turn off the wifi on your devices when not using it.
I found I was often getting bumped off, or was out of range or simply needed to reagree to the terms and conditions that Disney sets for the use of the internet. I believe this made my battery die a LOT quicker then if I was just using my 3G connection. So if you're, sleeping or busy on rides and stuff and don't need the wifi, I suggest turning wireless off until you need it.
Happy Travels!