Photoshop cs2 no background?

I want to use an image i created but i dont want the white background so that when i place the image into indesign, it only shows that image and allows my background to show up. I cannot for the life of me figure this out. Ive tried using magic eraser which got rid of my background white but i cant seem to save it so that I can use it without that white background. Anyone know what Im talking about?