Ok this is how I blen, other people do it differently, I find this the easyest...
1st start out with good source pics ( 2 will do for this)....
http://www.google.com if you dont know or
http://www.altavista.com
Assuming you have PS open....open a new doc....size it however you want
Open the source pics.....size them how ever you want...then copy and past them on to the new document you just made....
now I'm going to select the part of the picture I want to blend with the picture behind it...
now
set it to 30
press ctrl+c...now press ctrl+v (copy and paste....duh)
now over on the layers window click the eye of the pic you just copyed
see how that doesnt look good at all?
easy solution
drag that picture down to the button that it shows in this picture
do again if needed....
now in order for it to look better your gunna have to merge thos two pics that are featherd by pressing ctrl+e
now move the pics around until it looks good.....add a name and your set
finished product