The Cryptoterrestrials was released posthumously on March 15th, 2010. Fortunately, Mac gave numerous interviews on the subject of his book prior to his death, including this one with the Ballardian and an interview on Coast to Coast AM.
Since his death, a dedicated community of friends and readers has been working to preserve his legacy. Blazingbetta (aka Sarah Multiverse) has started a Mac Tonnies tribute site, and Capn Marrrk has been hard at work archiving Posthuman Blues. I talked to both of them via instant message.