Pooh and Tigger have a meet & greet outside of The Many Adventures of Winnie the Pooh ride. Check the Times Guide for hours. They also have these during the Halloween and Christmas parties.
You can also meet the gang at Crystal Palace for breakfast, lunch, and dinner at the character buffet. Would recommend making a reservation.
I believe Pooh also meets on a rotating basis at the U.K. pavilion in Epcot.