This is from Wiki: "Vespucci used a Latinised form of his name, Americus Vespucius, in his Latin writings, which Waldseemüller used as a base for the new name, taking the feminine form America. Amerigo itself is an Italian form of the medieval Latin Emericus (see also Saint Emeric of Hungary), which through the German form Heinrich (in English, Henry) derived from the Germanic name Haimirich" http://en.wikipedia.org/wiki/Amerigo_Vespucci

Wikipedia mentions the alternate theories for the origins of the name America. The best held one is STILL that it is named for Amerigo Vespucci. (Aren't you glad they went with his first name....you guys could have been the United States of Vespucci...Vespuccians.) "A few alternative theories regarding the landmass' naming have been proposed, but none of them has achieved any widespread acceptance. One alternative, first advanced by Jules Marcou in 1875 and later recounted by novelist Jan Carew, is that the name America derives from the district of Amerrique in Nicaragua.[16] The gold-rich district of Amerrique was purportedly visited by both Vespucci and Columbus, for whom the name became synonymous with gold. According to Marcou, Vespucci later applied the name to the New World, and even changed the spelling of his own name from Alberigo to Amerigo to reflect the importance of the discovery. Another theory, first proposed by a Bristol antiquary and naturalist, Alfred Hudd, in 1908 was that America is derived from Richard Amerike (Richard ap Meryke), a Welsh merchant from Bristol, who is believed to have financed John Cabot's voyage of discovery from England to Newfoundland in 1497 as found in some documents from Westminster Abbey a few decades ago. Supposedly, Bristol fishermen had been visiting the coast of North America for at least a century before Columbus' voyage and Waldseemüller's maps are alleged to incorporate information from the early English journeys to North America. The theory holds that a variant of Amerike's name appeared on an early English map (of which, however, no copies survive) and that this was the true inspiration for Waldseemüller."

There are two schools of thought here: