Are you talking about the British Prime Minister, Winston S. Churchill, or his American novelist cousin, "plain" Winston Churchill?
If you mean the British one, I'm pretty sure that a number of his books are available as commercial e-Books. He only died in 1965, so all his books are still under copyright protection. I recall seeing the 6-volume "History of WWII" as a commercial download.
Currently proofreading The Poison Belt, by Sir Arthur Conan Doyle.