Hi, Jacquelyn!
We are all huge Phineas and Ferb fans here at my house, so I can understand your family's excitement about becoming undercover O.W.C.A. operatives to help Agent P stop Dr. Doof's latest evil plan to take over the Tri-State area!
Agent P's World Showcase Adventure is included in regular Epcot theme park admission. You do not need to sign up ahead of time; when you're in the park, simply visit one of the Recruitment Centers to get started on your top secret mission. Recruitment Centers are located at Odyssey Bridge, Norway Pavilion, Italy Pavilion, and between the UK and France Pavilions near the International Gateway,
Missions are available for the following countries in World Showcase: Mexico, Norway, China, Germany, Japan, France and the UK. Each mission takes between 25 to 45 minutes to complete (depending on your individual pace and park crowd levels). Once you've successfully completed your first mission, you can continue your adventure by selecting a new mission. There are some really fun special effects and surprises along the way! My family has played many times and our favorite missions are in Germany, the UK and China.
And, of course, be sure to
meet Phineas and Ferb at Disney's Hollywood Studios near Streets of America! Join in the fun as the boys shoot a movie about - what else? - all their adventures on summer vacation! They typically greet their fans daily from 9:30 AM to 2:00 PM and again from 3:10 PM to 7:00 PM.
I hope this information is helpful! Please stop by the Moms Panel again if we can assist you further as you continue planning your vacation.
Wishing you a Magical New Year!