As a kid in school I used to rage against the celebration of Columbus Day, believing first 'how can you discover land when people already live there?' and second 'if Columbus discovered the land then why is it named after someone else?' Teachers rolled their eyes but never had any sort of intelligent response.
Thanks to the internet and some minor searching I see that Amerigo Vespucci was a bit of a loser and sailed to what was being called the New World after Columbus to make his wealth in pearls. He returned unsuccessful but wrote a couple of books about the trip, the second of which was a fake. However, communication not being all that speedy in 1507 the second book was published with copies of a map indicating "America" on the land above Brazil. I guess they figured it was too late to change it, so we are America. http://www.powells.com/review/2007_08_10.html