My husband swears up and down he has already seen this movie and it doesn't even come out in theaters until October 3rd. Has anyone else seen it or think they have?

It is definitely a new movie - the actors are all doing the talk show circuit this week. It's a true story about the man who invented time delayed windshield wipers. He claimed Ford stole the idea from him. Maybe your husband saw something about this man in a documentary or on a news program of some kind.

IMDB should always be your first stop: Flash of Genius (2008)
Says released October 3rd. Tons of early trailers were released.