[Tuzairius]

I have used photoshop to help explore wall colors a number of times now, and highly recommend it.
It really helps you visualize the space with your furnishings in place, and I have found it to be very accurate to the end result. It also allows you to explore painting one wall a different color (like a feature wall) from others, and helps you visualize the contrast of different colors in different spaces that are exposed to each other.
Each pic takes about half-an-hour to prepare and sometimes the color you first thought of isn't always the one you go with. Once you have finished in photoshop you can print the pics in color.
I have found though that you will still need to get paint chips/samples before commencing painting, to finalize the decision on shades be it a little lighter or a little darker, as different screens and printers represent the colors differently.