Gimp should be able to do this. At the moment I don't exactly know how, but it should do it. It works very similar to Adobe Photoshop. If you are acquainted to using Photoshop, there should not be any problem to do the same with Gimp. Otherwise, just take some time and try it - it is not that difficult.
All I want to do is create that natty effect where the profile in front is in full colour, whilst the background is in Black and White for a brochure cover.
Can anyone suggest some free software that can do this. Im using Windows Vista