the significance of blue in spanish?

so there is this dumb poem:
http://img214.imageshack.us/img214/7303/b722251b0814b2265df6694wa8.jpg

ive got it translated to something like this:
I want the prince
who is a color other than blue
as the blue prince
is always with others

I just don't understand why blue is chosen over the other colors. I've seen "principe azul" around on girls myspace so I assume it has some other meaning.

http://espndeportes.espn.go.com/news/story?id=663913&s=mot&type=story