CS3 Extended can work with Sketchup models if you export them to .kmz (Google Earth) format. If you spring for the fancy Sketchup, you get a lot more format choices.
[ edit: should mention that Photoshop won't add textures to a model, you only get to edit textures that are already there. For Sketchup, that would mean imported 2D images. Make sure that what Sketchup can do in that area is good enough for you, before getting too far into this. ]