Music rights

can anybody help me on how i can legally put someone elses music in my animation? to the point wher i want to publish it publicly.

i am making a short and in the end i might be brave enough to enter it in some sort of film festival…i know i have to ask permision to use whatever song i chose but how? what people or corporations should i write too?
in this first case i want to use the song “Mexico” by Cake…

all suggestions are appreciated, thank you.

I own a record label so this is a valid answer.
You first need to find out who the music is owned/registered to.
This can be done easily by searching the sites BMI or ASCAP.
Then you need to contact the owner and request the details for use.
Depending on the level of the Artist will usually determine the outcome.
It can be anything from acknowledgement to Thousands of dollars.

If you can not find the owner send me an email at owner at ryp records dot com and I will help you.

Little FYI - older music is sometimes outdated on its copyright and can not only be used freely but can be copyrighted by anyone wanting it!