Christine and I are watching Walk the Line and we like it pretty well. Most historical movies send me to Wikipedia to research the real history.
In this case, I'm looking to YouTube, too.
First off, Phoenix and Witherspoon's performances are amazing. All the more reason to look back at the real thing:
I Walk the Line - unfortunately (in a 'sad when relationships are broken', non-moralistic sort of way), Johnny was not 'walking the line'.
Jackson - Witherspoon is much prettier than Carter, but there's no denying Carter had all kinds of personality (as played up in the movie). Carter's vocal style is almost Broadway (which Witherspoon mostly did not match).
It Ain't Me, Babe - I was pretty sure this was a Bob Dylan cover.
Johnny Cash & June Carter, 1967, rare footage - interesting mostly for the interaction between June and Johnny he'd kicked his drug habit and they were married.
Upon finishing the movie, it could be called 'The Apotheosis of June Carter' ;-) She definitely comes across as a saint.