Pagan Artist has probably the easiest way with outstanding results-takes only minutes.  That's what I do.   Just remember to save it as something else-very simple and works great.  Here are the steps:  Determine which figure you want eg Sydney, or your favorite DAZ etc figure, locate the image map for him/her, bring it up in PS or PSP or any 2D software that is layer capable.
The background will probably be your 2d map. Ist layer, use a soft airbrush and put your favorite color to and around the eyes, use gaussian blur to feather it out, in another layer the cheeks.  Now adjust the transparency of each to taste, adjust hues etc.  When you are satisfied, first save it as a .PSD (PS) or .PSP (PaintShop Pro) etc.  Then merge everything together and save as a .jpg, .bmp etc in a place where you can easily find it.

Load that figure in Poser, go to the Material Room, click on the figure's face,  go to PoserSurface, click the node Color Texture's tiny, very tiny white printing beside image source, another menu will pop out called Texture Manager, select browse, go to where you saved your image map that you named something click on it,  then on Open, Texture manager will pop up again, click on OK and you got it. 

See all those male plugs, if you click on anyone of them, new node will appear, passing your cursor over it will display  five subnodes Math,  Lighting, Variables, 3D textures, and 2D textures, it is in the 2D textures that you will browse for your figures skin wraps. By the way, you can using any .jpg etc you want, landscapes space scenes and paste as the face or body of your character with some very interesting results.

Have fun--Plutom