What is the consistency of the mass? Is it actually a fleshy mass? Because I have seen dirt in a cat's ear that has been mixed with ear mite excretions that looked like that, and it was able to be removed with a Q-tip. If you try to clean it and find that it's not something that will respond to gentle prodding with a Q-tip, a visit to the vet is in order ASAP. How old is your kitty? Has he had any problems with that ear previous to this?
Ghilly
Better pictures
http://i45.photobucket.com/albums/f66/jasoneggleston/1.jpg
http://i45.photobucket.com/albums/f66/jasoneggleston/2-1.jpg
http://i45.photobucket.com/albums/f66/jasoneggleston/3.jpg