Hi Denise:
Walt Disney World posts a calendar for its theme parks that display various information including Park hours, Extra Magic Hours, operational updates, entertainment and special events. These calendars are generally posted several months in advance, and while anything can happen, I've always found the calendars are posted at least several weeks in advance of being able to make your 180 day advance dining reservations.
When I look at the
Hollywood Studios Calendar for the week in question, I see that Fantasmic is showing every night at 9:00 pm (schedules are always subject to change, of course). Visit the
calendar page for Hollywood Studios. Then click on the June 2012 calendar link from the drop down menu on the top right of the calendar. Don't forget to click on the desired day to find out the time parades, shows and other events are scheduled for the day in that Park.
As schedules are subject to change, after arriving at the park, check the Times Guide at Disney's Hollywood Studios to confirm schedule and show times. Since Fantasmic! is an outdoor show, it is subject to cancellation due to inclement weather.
Enjoy your vacation.