According to Wikipedia Curbs resigned from Charlton.I couldn't believe it when they binned him off. Even more couldn't believe it when he left West Ham under a bit of a cloud on the eve of a season, having pulled off a minor miracle in keeping them up with Tevez scoring goal after goal.
"After declining to extend his contract with Charlton, Curbishley agreed to leave the club at the end of the 2005–06 season. He received a standing ovation from the Charlton supporters in his final home match in charge against Blackburn Rovers. "
He resigned from West Ham too but this was constructive dismissal (the club broke his contract regarding player sales) and he was awarded £2.2 million compo.