you can download trial version first and google a sn for good, :-).
http://www.microsoft.com/mac/
also, there are other office suite can be a replacement of ms office on mac.
(why not use appleworks coming with mac machine purchase?)
other downloadable sw for mac can be found by google, like:
http://www.fwnetwork.com/mac/
http://www.download.com/3101-2036-0-1.html