I need the name of an old Western with james Stewart and Henry Fonda. They are in some kind of saloon and a guy calls one or both of them a son of a . James Stewart grabs the guy and says something like don't ever talk about my folks like that. My parents were poor dirt farmers and so on. So the guy appologises and leaves. Fonda says.. now you know our parents were no good rustlers... HELP!! Thanks...

That kind of reminds me of How the West Was Won.

How the West Was Won (1962) (http://www.imdb.com/title/tt0056085/)

That would be 1970's The Cheyenne Social Club. Great movie!