It depends on what your asking. If your looking to add a colored pattern, you can copy the pattern, put it on a seperate layer. If the model is wearing a light colored outfit your in luck. Take the layer with the texture and multiply it. This will allow all the shadows to show thru, giving a more convincing look. As far as molding it you will need to place with it. version 6 has a warping ability to the layer which may help. As well you will need to do some cloning as well as duplicating the pattern on seperate layer and put then together. Also note, you would want to put a layer mask that is the out line of the article of cloths. This way you can move a round the pattern without re clipping it again. If It's a texture you want to add. Load a texture in a channel, load it, then darken the shadows/brighten the highlites. Hope this helps! feel free to email me w/ any questions.

lightwave, photoshop, oreo's...tools of the trade.