The latest edition of AAP is out! Go buy one here. This is the 2009 edition, an update from the 1995 edition. It is twice the size of the previous edition which much more information, including the ancestries of the 43rd and 44th presidents.
Counting just colonial ancestors, I'm related (distantly!) to Fillmore, Pierce, Grant, Hayes, Garfield, Cleveland, Taft, Harding, Coolidge, Hoover, FDR, Nixon, Ford, and both Bushes (total 15). Since Washington has no close kinships via colonial ancestry, they stretch him back to 15th century England. Using that criterion, I also get Washington, J.Q. Adams, Carter, and Taylor. Michael is related to T. Roosevelt, Van Buren, and Lincoln. So all told via marriage and others, that's 22 presidents or half! That shows you how insular that group of men have been.
Disclosure: I'm in the acknowledgments of this work (and I was for the 1995 edition too). My work appears in Garfield, Lincoln, and Hayes.