Cinderella's Surprise Celebration has several shows each and every day. The earliest performance is usually at 9:40am.
Other shows in MK include Goofy's Country Dancin' Jamboree at the Diamond Horseshoe Saloon, The Dapper Dans and the Main St. Philharmonic on Main St, Tomorrowland Countdown band, and the Flag Retreat in Town Square. All show times are printed in the weekly 'Times Guide' available with guidemaps.
There is more live entertainment at Epcot. Stevesoares.net (?) has a very good listing of featured acts and times.
Some of my Epcot favorites are Le Mime Roland in France, Oktoberfest Musikaten in Germany, Dragon Legend Acrobats in China, and Kristos in Future World Innoventions Plaza.