help with colours

Hi,
This is gonna be real easy for some of you, but I haven't really used photoshop proper for 10 years and i'm well rusty!

I've got PS7 and what I need help with is this.

I've got a photo of a plain white T shirt but would like to change it so it can be used for 10 different colours.

How do I go about overlaying a colour on top so that it shows the creases and shadows of the original white shirt but looks like a new colour?

I've tried but i'm stuck and it's now hurting my head!?!

Can someone shove me in the right direction please?

Thanks

set the layer mode of your colour to "colour", adjust hue/saturation etc to suit