I recently obtained a copy of "The History and Genealogy of the Witherspoon Family (1400-1972)" by Joseph Bailey Witherspoon through an interlibrary loan. The book draws on 40 years of genealogical research of the author and draws on 200 years of research by others. The book only covers individuals with the surname Witherspoon (except for the earliest listings, which have other spellings) and the authors admits that literally thousands of Witherspoons are omitted.
If you have any questions on the Witherspoon family, post here and I will try to answer them. I do not have much time to work on this, and, strangely, the index is not entirely alphabetical, but I will do the best I can.
I will also check my line on the Witherspoons for errors (the first listed Witherspoon, Alexander Wetherspun is my son-in-law's 16 great grandfather) and try to do some merging along the line.
It is due on 11/15/2010, but is renewable. Since I am the first person to check it out in 17 years, I may be able to keep it for a while, but you never know.