Hi Beth,
We don't know a lot about the Summer Nightastic Fireworks Spectacular. Here is what the press release says:
"What could be more summery than fireworks on a star-studded night? Magic Kingdom will treat guests to "Summer Nightastic Fireworks Spectacular," filling the night sky with vivid colors and brilliant visual effects while whimsical music fills the air."
Wishes will not be performed during Summer Nightastic which is scheduled to run June 6th - August 14th, 2010. We haven't heard if Wishes will return after that time or not. Keep your eye out on the
Disney Parks Blog as well as their twitter accounts DisneyParks and WaltDisneyWorld where you can find out all the breaking news.
While I love Wishes, I'm excited to see the new Summer Nightastic Fireworks Spectacular because as in true Disney fashion, I'm sure it will be amazing! Wishing you many magical memories :-)