Up early-ish this morning and found a message on email from the Genealogy Publishing list on Yahoo. There were a couple of useful posts regarding getting your book in print.
One link: http://otter-bay-books.com/guide-for-authors/ seems like a good place to start. There is lots of advertising text, but even that in interesting and useful in helping choose a publisher. This is just one example of a publisher. It has some guidelines for margins (their "Roadmap") that I will use in my own publishing efforts.
Another poster suggests using Lulu.com for 'publishing-on-demand'. I have heard of Lulu before but have not been there myself. It might be instructive to see what they have to say.