Here's a REALLY quick one that is 'similar' to what you are asking, and I mean, QUICK and similar too...
http://4dw.net/crisp/poster.htm
I say "quick", but I spent about 45 minutes on it doing it from scratch, and it could probably be done in less
time with an action.
This is a large file too, 'cause it's a ROLL-OVER, so both images have to load first, so be patient...
This is 'just kind'a' how I'd do it, I took the colors off of the Bogart poster supplied, just to kind'a show the
poster look, which works on that particular poster, but not on this woman.
Bogart
http://www.musicman.com/00pic/4180.html
Anyway, it's quick, and not a really good image to work from, I believe that the starting image needs to have
the necessary 'look' to it to make it even begin to look like it's a poster.
My example is a prime example of what style image NOT to use!
Like Pindaro says, it would be better to see the image you have to give a better idea as to how it could be' done.
Randy