How do I create a macro to return all possible combinations of letters?

This was not quite what I wanted but good enough - many thanks!
The reason for it was not academic at all, but I am in the process of "meshing" 2 names into one and wanted to see all the possible 8-letter anagrams made up of equal parts of the 2 existing 8-letter names, to see if any really stood out. the solution given by Armando was the best I have found, I just have to pick 8 letters to use rather than them being randomly selected!