Hi Jeff,
Great question!
You can begin making Advance Dining Reservations at 6:00 AM EST 180 days in advance
online via the Walt Disney World website or at 7:00 AM EST 180 days in advance by calling (407) 939-1947.
The actual times that Dinner is offered will vary at each individual dining location and will also depend on what time of year you visit. If you wish to see what hours Dinner is served at any particular restaurant, simply click on the restaurant of your choice and this information can be found on the right hand side of the page underneath the blue box which is titled "Book Your Trip."
For example, Dinner is served at
50's Prime Time Cafe from 3:30 PM - 9:00 PM on September 16, 2016 and from 3:45 PM - 7:00 PM on February 28, 2017.
Wishing you a magical trip filled with memories which will last a lifetime!
Emma