Here's a link to the most useful tutorial I have so far.
www.thinkdan.com
I've had a lot of questions about this. I will probably be doing a tutorial at some point in the Ezine, but basically you wan't to import your photo into the layout. I like to change the opacity of the layer on some of my layouts but that's optional. Add a mask (the square with the circle insie on your layers palette). Select a soft brush and at varying opacities begin blending. It really is just practice after that
hope this helps
Anna