pink to blue

I’ve been wondering about replacing colors in photoshop. I think I’m doing thins the hard way. Let me start here. If I take a shade of blue in RGB form...lets say 0 128 255. And then I move move the blue to the red, red to the green and green to the blue, I end up with 255 0 128, which is a pink the same shade as the blue. My question is this. Say I want to do this to all my shades blue in an image. (move the blue to red, red to green, and green to blue) is there an easier way to do this than changing the image to indexed color and editing each color in the color table individually. If I do that I’m only able to edit shades of blue in images that are saved in indexed color.

I'm using Photoshop 7.0 on windows XP.

...select -> color range could be one way?