"To aim at" is to target someone or somthing, usually with a weapon or some other projectile, such as a baseball, for example. "To aim to" is an in formal way of saying "to intend to" do something....
Actually, Nazi is just an acronym for the National Socialist Party, as it is in German: Nationalsozialistische Deutsche Arbeiterpartei. The term had no negative connotations in Germany, or indeed in...
AIM is free to all users, but first you have to download the software (It's easy). Then get a screenname. Getting an AIM only asks for an e-mail and some personal info like your name.