presumably (gay symbol aside) it is representative of some sort of Utopia or mytholigical journey/dream - trying to find the source or end of a rainbow... is like a horizon - you can see it but you can never really SEE it...

i don't know - i presume it's a gay symbol simply because of the bright "pretty" colours rather than anything deep...

Jess - I think what you said is very good, sounds right to me... while it's the sun after the rain, i think the use of it in a night-time setting in literature and music means something else... possibly its just something magical, but then again it could be some sort of foreboding... a world of black, with the "light at the end of the tunnel"... that never ends...