The 2008 rates should come out mid-August. I was able to book our 2006 trip on August 12, 2005. I was able to book our 2007 trip on August 15, 2006. I tried to book each trip at the end of June and was told, both times, that the next year's rates aren't published until early to mid-August.
I told the reservationist (in June) that I wanted to get an idea of what my trip would cost. She gave me a quote for 2006 rates and then she said to add about 18% to it. She said every year the packages go up about that much.
She was right on the money too. I was given a quote of a little more than $3,000.00 and the package ended up costing $3,334.69.
You should be able to call now and make a room only reservation and change it to a package later.
Hope this helps, Lisa