I have exactly that!
Songs are colours to me.

For instance, Smells like teen spirit would be purple, whilst the Foo's Learn to fly would be a greenish/teal and the macarena would be orange.
(Colonel Santiago Introduced surprised kitty to the world., Fri 9 Apr 2010, 17:00, 1 reply, 16 years ago)

mine is more like
individual notes and sounds having colour or form.
( Citizen Cavy Admires your passion for conformity, Fri 9 Apr 2010, 17:02, Reply)

Clearly way more intense!
EDIT: Actually, now you mention it, if I'm playing a synth and fucking about with the noises, the texture of the sound would affect the colour I hear. Individual notes don't have the same effect.
(Colonel Santiago Introduced surprised kitty to the world., Fri 9 Apr 2010, 17:03, Reply)

very difficult to describe, though
I have it with ideas, too, which means I can work through concepts in my head that way (sometimes knowing the end product of an argument because the colours and shape fit) but then have to work backwards to put it into actual language
( Citizen Cavy Admires your passion for conformity, Fri 9 Apr 2010, 17:05, Reply)

Ok, in that case, you're just a good old fasioned mental.

(Colonel Santiago Introduced surprised kitty to the world., Fri 9 Apr 2010, 17:06, Reply)

YAY!

( Citizen Cavy Admires your passion for conformity, Fri 9 Apr 2010, 17:06, Reply)