Hi, after further research, you can use Photo Pos Pro, which is free.
The download link is:
http://www.photopos.com/index.asp?Re...&SoftVer=1.8.5
Once you have installed it, go to Help, search users guide, and enter the word 'clone' in the search field, you will then get an example of putting heads on other bodies
I hope this is useful to you.