Everybody calm down - Will Smith will NOT TO BE Captain Amerika. Denzel Washington does. (Muhaha - i'm very funny today:D)
Several Days before Captain America Fans got a Heart Attack because Derek Luke tells, that that Marvel has offered the part of Star Roll of the Movie to Will Smith. (I dont understand, why - If President may be Afroamerican, Leader Hero may Not?) Upon hearing the news, AICN immediately started contacting their many sources at Marvel and the response was the same. Luke has no idea what he's talking about.
Apparently, Marvel has never offered Smith the part, nor did they approach or entertain a conversation about him playing Captain America. So there you have it, the world makes sense again.