Leland,
Disney offers a service called
Online Check In. The service allows you to check in online from home, BEFORE you leave on your trip. You can do it as far as 60 days in advance of your arrival day. But why would you?
First of all it saves time. When you arrive to your resort hotel, everything is already done. You get in a separate line at check in, reserved for Online Check In guests, and just pick up your packet. They don't take your credit card (because you already did that), they just ask for your ID. I estimate it saves me on average, 15 to 30 minutes.
Second, you can put in a preference for your room. They will ask about a few variables that you can select from (room on a low or high floor, desire to be near transportation, etc.), and will do their best to accommodate your need.
Now some people don't like it, because they want to request specific location rooms when they get to the resort. But this does not preclude that. The first time I used it, many years ago at the Animal Kingdom Lodge, I did not like my room location. I asked if they could get me closer to the lobby. They said 'no problem', and I still got my room key and packet within a few minutes. As a matter of fact, I kept track of where I would have been in the regular line, and I was still done before two people who would have been in front of me in the normal check in line.
I recommend it highly, but if you are not sure, you don't have to do it.
Also, no, they don't alert you via e-mail when you can do it. So mark 60 days out on your calendar! Write me back if you have any other questions.
Have a magical vacation!