The Timothy Leary Archives project at the New York Public Library has a Web site, and Robert Anton Wilson's name pops up in a couple of places on the site.
A description of the papers being made available eventually says that they include "Thousands of letters to Leary, many from luminaries of the 1960s era, including Aldous and Laura Huxley, Gerald Heard, Alan Watts, Jack Kerouac, Allen Ginsberg, William S. Burroughs, Peter Orlovsky, Charles Olson, Arthur Koestler, Huston Smith, Walter Houston Clark, Walter Pahnke, Humphry Osmond, Al Hubbard, Oscar Janiger, Cary Grant, Charles Mingus, Maynard Ferguson, Michael Hollingshead , Robert Anton Wilson, Gordon Wasson, Ken Kesey and Augustus Owsley Stanley."
And here's an excerpt from an interview with Joi Ito, Timothy Leary's godson:
Q: In this video, he calls you his godson? What’s the story behind that?
A: I met Tim on the evening of my birthday when I was turning 24 in Tokyo, in Roppongi, through a mutual friend, David Kubiak. I remember, because I asked him about the number “23″ and the whole Cosmic Trigger book story by Robert Anton Wilson, and asked Tim if he had really talked to aliens. Tim said all that was a big joke. The whole 23 thing and alien thing. We laughed and laughed.
We became close friends after that, and started collaborating on a book. I don’t remember exactly when it was, but somewhere along the line, we decided I would be his Godson. Tim had this thing. He would adopt god children.
One more thing I remember, was when I asked him what it meant to be his Godson. He told me that it was my duty as a godson to teach him – that he adopted godchildren to be his teachers.
The archives recently released a transcript of Leary talking with John Lennon and Yoko Ono.