Read 'em and weep true believers: Bucky and Peggy Lee will be in the Cap movie. Does this movie really need a teenage sidekick and a love interest? I don't know. Maybe purists will say the The First Avenger would be incomplete without ole Buck' and a girlfriend for Cap. I can live with this if and only if these are the only supporting characters that the audience has to invest in besides the villain, The Red Skull. If the script includes other WWII era superheroes, like the forgettable Invaders, then the story will be too busy and too much to digest.
Me thinks Cap, Red Skull, Bucky and some eye candy = plenty of characters - anything more than that and you risk costumed character overkill.
For what it's worth, the rumors are that some Gossip Girl actor named Sebastian Stan is cast as Bucky Barnes and that Alice Eve is in the lead for the role of Peggy Lee. It hasn't been confirmed, but Matrix alumnus Hugo Weaving has been reported to land the villanous role of the Red Skull. So far, so good ... although the Bucky costume must be handled ever so carefully. Yes, he looks like a red, white and blue Robin from Batman.