theres soo many "versions" or "rip offs" of am, and those are the ones i really like.
i use dead aim which i think is 50x better than reg aim.
but ya aim is pretty much like msn, but its my ur screen name, not ur email addy.
u can also add info about that buddy on ur buddy list. like little buddy comments so u know who that person is or anything u want. and as u hover over that name..the little buddy comment u added will show.
with dead AIM i have all the buddy windows(instant messengers) all in 1 tabbed window instead of say 10 diff windows. and just like msn it alerts me when people sign on.