Hi Beth,
You will be able to make your dining reservations 180 days prior to the start of your trip, I used the calculator at
www.pscalculator.net which told me you can call on January 12th. As you're staying at a WDW Resort you will be able to make the first 10 days of your dining reservations on that date too!
You can make your reservations either by calling 407-939-3463 from 7am EST or online from 6am EST. To access the online booking form click
HERE find the restaurant you'd like to book and click the "book a reservation" link. You will need to have your WDW resort reservation number handy to make reservations beyond 180 days.
You may also like to view the 2010 Deluxe Dining Plan brochure
HERE, this tells you all about the plan and lists all the participating restaurants, more are being added all the time so be sure to check the link regularly.
Have a fantastic trip and I hope you get all your reservations,
Jo