Your name cited fawningly and obsequiously on the credits page at the book's web site, http://producingoss.com/ . (Your name can include the name of an open source project you work on too, if you want.)
The above, plus I will dedicate one of the book's version control commits to you, or to the project, person, or organization you designate. Note that all the book's vc checkins go into a publicly visible repository. (This reward is new -- I added it after the campaign had been running for 20 days. Many thanks to Michael Bernstein for thinking of the idea!)
All of the above, plus an hour of phone or IRC-based discussion, to be scheduled at mutual convenience in 2013, about an open source project you are involved in, or interested in, or thinking of launching, etc. (I'm also happy to get your thoughts on what should go into the second edition of the book, if we have the conversation while I'm still writing.) Alternatively, our conversation can be about what the reward for this pledge level should have been.