First of all, I've been calling Disney reservations almost every day since June 13th to find out when the 2008 rates will be posted. Mid-August seems to be the most common answer. Some have indicated it could be as soon as early July. I did have one CM tell me that the computer system (including the website) is updated every day at Midnight and to keep checking it every day. (That's no problem 'cause i've been doing that already)
As the previous posters have said, you can book a room only package right now but it will be at the 2007 rate. The price will be adjusted as soon as the 2008 rates come out.
Now, to the question relative to if you book a vacation and then a special comes out. This happened to me this year. I booked our June, 2007 stay on August 15, 2006. Sometime about mid-way through my paying on the vacation, Disney came out with a room discount and free ticket upgrade.
I found this out by checking "special offers" on the
www.disneyworld.com website. I immediately called 407-W-DISNEY and told them what I had found online. I was able to get two nights of my 10 day stay at a slightly discounted rate and I got the free ticket upgrade (water parks and more). The vaule of the savings and upgrade was over $300.00! I wouldn't have cared if it was just $30.00, I'll would have taken it!
Hope you find this information helpful, Lisa