At the end, all Wichita needed was a red jacket to match her Zoey ponytail.
Tallahassee's "farewell" to Columbus is "That'll do, pig", from Babe. Columbus even calls him out on it.
Also, Tallahassee makes a few references to Deliverance during the supermarket scene, the banjo being one aaaand...
"You got a purty mouth!"
A subtle one from World War Z. In the book, a guy in the Long Island mansion brags about his exact copy of Tony Montana's AK-47 from Scarface, despite the fact that Montana used an M-16. Cue Zombieland's opening, with a guy dressed as Tony wielding a Kalashnikov.
Tallahassee's ride on a roller coaster swarming with zombies brings to mind rail shooters like House of the Dead, especially Carnevil, which, as it suggests, has you on a roller coaster fighting zombies.