I <3 the smudge tool. Another tip, if you dont like flattening the whole thing; make a new layer, go into image>apply image. This will make a copy of the image in that new layer.
i dont flatten layers at all. create new layer, "Image > Apply Image" gives a flat image on that layer of all that is visible. or select all > copy merged > paste on new layer. this way you can have a flatten version to work on and the "source" layers all in one file :)...just group stuff to make things neat oh and great…
Man, I can't express how much I love little tutorials like this. They're pure gold. Anyways, have you considered CS5's "Mixer Brush,"JFletcher? That sort of thing would seem like awesomesauce to someone who likes to do things the hand-painted way! You can mix certain or all layers with a single brush stroke, or paint…