Evan has already written an article about Pidgin already where he mentioned Adium, but I felt that Adium deserved its own article considering how great it is.  Back when I did not have a Mac, Adium was the application that made me jealous of Mac owners.  Adium supports all the major IM platforms and even a bunch that I have never heard.  The current beta version even supports Facebook chat.  Adium has a large library of Xtras that includes everything from user interface skins to a plugin that lets you …