On TV: Hilary Duff, Clay Aiken, Ashlee Simpson

Pop acts on television this week include Fefe Dobson, who appears on MTV’s ‘Total Request Live’ on Monday; Hilary Duff, who appears on ‘The Late Show with David Letterman’ on Wednesday, and ‘TRL’ and ‘Live with Regis and Kelly’ on Thursday; ‘American Idol’ runner-up Clay Aiken, who performs on ‘The Early Show’ on Wednesday; and Ashlee Simpson, who performs on ‘The Late Show’ on Friday.