If you know what kind of room you want, call Disney now (or use a TA) and book a room-only reservation. You'll pay first night's deposit, which will likely be higher than the price you'll actually pay per night if you go in January, as the deposit will be based on peak period pricing and January traditionally is value season. Pricing seasons change in February, I think, so double check before you choose your dates. One of the best "discounts" available, to my way of thinking anyhow, is booking in value season. It's a rare discount in any other season that gets you much lower than the value season price.
In August, they'll likely release the 2009 rates. You can call back, adjust the pricing on your room (from 2008 peak price to 2009 value for instance), and either turn your room reservation into a package reservation if that's your plan or apply a
AAA discount to the room-only reservation if you have AAA. (If you want AAA discounts on a package, you have to reserve with a AAA TA directly.) Later in the fall, any discounts for passholders or other groups will be released. If you qualify for one of those, you can call and have that applied to your reservation at that time. Basically, you don't have to wait for rates and discounts to make reservations like the pp's mentioned. I'm only repeating all that to clarify that you don't lock in a price or preclude yourself from getting any available discount by acting now. Probably not a good idea to wait, as things book up.
And, as a note to the poster who mentioned checking in on NYE, I'd consider that very carefully. It sounds like they're willing to give you a set package price based on 2008 pricing since you arrive in 2008, but you might check how the pricing works out if you arrive on Jan. 1. When we arrived last year, Jan. 1 was the first day of value season. Given the standard annual increase in resort prices (a few percent per night), the price for staying one night in holiday season (several hundred dollars more at WL than it would cost for the same room the next day) was still a lot more than we paid for the annual resort price increase for the rest of the week combined. That might be lessened in a package somehow, but, in my experience, paying for a night at "holiday season" rates and locking in 2008 prices for the rest of the week is more expensive than paying for value rates the whole week, even with the annual increase factored in. I hope that makes sense ... considering Disney pricing is like going in circles.