Princess and the Frog seems to have its share of references to other Disney films. Here are the ones I noticed, post if you saw any others. Possible spoilers ahead for those who haven't seen the film.
- The magic carpet from Aladdin is being cleaned on a balcony on the right side of the screen during the opening lines of "Down in New Orleans"
- Lots of princess references in Charlotte's room, including doll dresses reminiscent of several Disney heoines and her dressing screen, which has a picture of a castle on it. It looks like either the Beast's castle or Prince Eric's castle. It's somewhat hard to see.
- Tiana rides streetcar A113 during "Down in New Orleans"
- There are several possible referential costumes during the masquerade ball, including an Aladdin and Jasmine and an Ariel
- I've heard that the Genie's lamp is visible in Mama Odie's house, but I didn't see it
- There's a giant King Triton float during Mardi Gras, and caricatures of the two directors of the film are throwing beads from it.
- Louis is riding on an Aztec/Mayan themed float alongside someone wearing a llama costume--possible Emperor's New Groove reference?
- The Firefly Five plus Lou in Tiana's Palace at the end are a reference to the Disney band Firehouse Five Plus Two