I do my lines on my mac all the time... you need Parallels or bootcamp. I prefer Parallels because you can run windows and mac OSX at the same time.
Heres a pretty good video on how to install it:
http://www.youtube.com/watch?v=vJCAw...eature=related
Paralells is not free, you can take 2 approaches: Buy it at futureshop or "Buy it" from the internet. *cough*torrent*cough*
What you will need is:
-Copy of Parallels (I use Paralells 3.0 I think - but 4.0 just came out last month)
-Working CD of Windows XP, Vista, 7... whichever one you have.
-Working CD Key for that Windows disc.
So when you get that all running you need to run paralells and go through the sim procedures to get the sim program to work:
http://cphl.calgarypuck.com/pages/rosters.html
Download the Support Files - install them while you are in paralells.
Download the GM Editor
Download the Roster file
You will get an error I believe when you first open the GM Editor - dont worry about that just click OK and click File->Open then select the roster files.
You should be good to go then.
The downside to this is you have to open parallels everytime you want to make your lines but that shouldnt be a big deal. Hope this helps.