GrafJ

I am wondering if there is a way to make the white background of an image appear transparent on a page. I'm sure I could do this by deleting the white background to be transparent but it would be nice if there was a easy tool or layer adjustment to do this.
Previously when we used M$ publisher it had a tool where you could select the white in the background to make it transparent. 

Hello,
 
If I have a black and white pixel layer (or a grayscale pixel layer), is there a way for me to select the white area of it? I'm essentially creating a mask on a pixel layer, but now what to select it so I can actually apply it as a mask on a mask layer. It's a luminosity representation, so I ideally want to transfer it as is to a mask layer.
 
Cheers!