A great ambassador of the Negro Leagues, and baseball in general is John "Mule" Miles. He's not the most famous player (or even the most famous player nicknamed Mule), but from what I read, he was a great hitter, and played while the Negro Leagues were still on par with the Majors.

I wrote him to request his signature a couple of months ago. He sent back three ICs with different sayings, and a nice letter answering my questions. Recently, I wrote him again asking that he sign for my brother in law for Christmas. Not only did he send him signed ICs (the SASE was my BIL's address) he also sent me another nice letter. I included a donation each time, and I would suggest that others do the same, but I bet he would sign for free. In his second letter he explained how players of his generation are old and dying, and when they pass on, they take a piece of history with them. He feels it's his duty to let people know about those players and how they played the game. We need more guys like Mule Miles in this world.

http://www.flickr.com/photos/56028463@N06/5182979877/