My take is that he started to dissolve his collection a few years ago. I saw some of the items listed on eBay, Heritage, and other sites in the last year or so. Also, many are being sold by JoshuaTree
http://joshuatreeauctions.com/autographs.html
There are some sweet items there but WAY overpriced.
On a side note, here are some other HOF collections on the PSA site:
http://www.psacard.com/DNASETREGISTR...site.aspx?c=37