It's all under the cut..
1. open the pictures you want to manip
2. place the pictures into one canvas. Resize that canvas to desired width/height.
3. then start to erase what you don't want to be seen from the picture ontop.
4. you're going to want a common background, so click the clone stamp , and hold down the 'alt' key, click on the place you want to 'clone' and click on the place you're copying it to. (It's easiest if you hide the top layer)
5. After that , make the top layer visable, finish erasing what you want to be erased , and place it to where you think it looks best.
6. crop the picture as you wish , and change the coloring so the pictures you've just maniped have the semi same coloring.
7. play with the coloring , cropping , effects of the picture.
my finished result :
(obviously not my best , but i did this in about 10 minutes...spend more time on it if you want a better result)
Let me know if this helped at all, and if you want me to do a tutorial on something else.