How do I make a shape appear to curve around an object

Hi,
I'm trying to make a shape appear to be on a ball in an image. I can't seem to get it to look curved so it looks like it is really painted on the ball. I just looks like I added it and is not natural looking. I've tried transforming the image, but I can't seem to get it right.
Does anyone have any advice on how to achieve this?
Thanks in advance.
Sam

Try the Filter>Distort>Spherize.

Or upgrade to PS CS2, the transform tool there transforms and warps anyway you like. Joy!