During my internet travels I found a really neat little plug-in called curvemeister. It looked great - finally integration of a live histogram behind a curves window. HOWEVER it wasn't available on the mac! What a pity - would have been such a good way of working.
I've since discovered you can sort of get this working in photoshop by going to your showing your histogram pallette (from the window menu) and then when you go to curves - you get a before and after preview in your histogram pallette, while your working in your curves pallette - so PC users can now also get the same thing without having to shell out the cash for curvemeister.
Hope this helps someone out there
Cheers.
