I just finished the American Wife, by Curtis Sittenfeld,which is a fictionalized account of the life of Laura Bush. I found it very well written and difficult to put down. I should add that I really enjoyed the first part of the book, but the last section that tells of her life after her husband became president was way too long and preachy. I ended up skimming most of that part.
I was impressed by all the period details she incuded in the book, especially from the 60s and early 70s. Another thing I noticed is that the main character, Alice Blackwell, is supposed to be writing this as she looks back on her life as a way to explain why she ended up being first lady in a Republican administration when she had beliefs that were more in line with the democratic party.