hi there,
I'm the mac user too, u can use LR or LM although you are using macintosh. What you must do is install the boot camp application on your mac.Its allow u to run windows on mac.you may see the thread here,it suggested by longtalldrink
http://forum.brillkids.com/little-reader/able-to-run-lr-on-mac-using-fusion-or-other-parallels/msg18569/#msg18569for the boot camp application, pls go here
http://www.apple.com/macosx/what-is-macosx/compatibility.html