There is free ethernet in the DVC resorts. There's a note that it costs $9.95 per day for normal guests, but DVC members get it for free. We used the direct hook-up in BLT just last month. I'm going to follow everyone's tip and bring a wireless router with for our December trip to Kidani.
Not intentionally, but often renters do not get charged. However, if you do get charged, you will have to pay it because it's a perk that's reserved for members only.
I posted this on another thread, but newegg.com has an ASUS Wireless Access Point for $32 after rebate. http://www.newegg.com/Product/Product.aspx?Item=N82E16833320025 It's only a 802.11b/g, but for surfing that's plenty. It's really tiny and comes with it's own carying pouch. It does take some configuration because there are 4 different "modes", but nothing too complicated.