S/D has unlimited local-access broadband in guest rooms; it is covered under the daily resort fee that you pay.
There is wireless access in the common areas of Disney resort convention centers; that would be GF, BW, Y&B, CR, and CSR. It's not free, though, you have to buy a code. I think it is around $10/day; call one of the convention concierge desks to ask.
There are 802.11b ports all over the parks, but they are secure ports used for CC transactions; no free hotspots.