Trivia: Breckin Meyer, who plays Jon, is allergic to cats in real life.
Trivia: Bill Murray agreed to be in the film without reading the full script upon seeing the name "Joel Cohen" listed as a writer. It turns out he thought he was signing onto a film co-written by "Joel Coen" of the Coen Brothers fame. It wasn't until he began recording his lines sometime later that he realised his mistake.
Answer: The song is called "Holla", by the Baha Men (of "Who let the dogs out" fame).