When The Hollywood Reporter announced Don Cheadle had replaced Terrence Howard in Iron Man 2 as Jim Rhodes it was said negotiations "with Howard fell through over financial differences, among other reasons." Well, according to an NPR interview with Howard I found via CHUD.com that is all one big surprise to him.
When the subject is brought up by interviewer Scott Simon Howard replies, "Yeah, I found that out, too.
"It was the surprise of a lifetime," Howard continued. "There was no explanation. [The contract] just...up and vanished. I read something in the trades implicating that it was about money or something, but apparently the contracts that we write and sign aren't worth the paper that they're printed on, sometimes. Promises aren't kept, and good faith negotiations aren't always held up."
I didn't listen to the interview myself, but Russ Fischer at CHUD says the Iron Man talk begins around 4:31 if you wanted to give it a list right over here.
Who's telling the truth? Howard or Marvel?