plz help me !

hello everybody ! i'm new to thin forum and maybe i'm not posting in the right category, plz excuse me and plz guide me , too !
my problem is that i want to make a wallpaper similar to the one i'm attaching here... i have a new background and a new picture with a girl but i'm not very skillfull in photoshop to combine them to result something like this !
could anyone guide me step by step so i can obtain something like the picture i posted here ?
thank you !


P.S. seems that i can't attach the picture , but you can see it here : http://www.aivanet.com/gallery/win/pages/windowsxp_061_jpg.htm

you can see it better here : http://www.yvee.3x.ro/wallpapers/Win_XP_Wall/windowsxp_061.jpg