I have not heard anything regarding PT for the Mac. Sorry. You may want to look at running a VM with Windows or even better real equipment. You may also wish to make a request to the Fink team to port GNS3 over to the Mac http://www.finkproject.org/ but doubt that you will see PT there anytime soon.. I could be wrong though..
If you do decide to run GNS3 then check out the doc I linked for it!
I'm not sure about GNS3, but Dynamips (the underlying stuff anyway) runs fine on a Mac. I set up 12 routers without problems on a Mac Mini.
Since Dynamips doesn't truly support switches, you CAN bind the interfaces to REAL interfaces. When I set mine up (just to test) I had three 4-port USB hubs and a total of 12 USB 10/100 Ethernet NICs. They were then plugged in to four REAL switches (the 3560 8-port is a less expensive alternative to the 24-port version).
So you can get a FULL lab (in my case it was CCIE lab, but you can certainly do smaller setups!) on one PC and x-number of real switches!
Thanks B Haines for the Doc, it was very helpfull. However, GNS3 didn't work on my laptop because it seems that isn't CISCO image for Mac. For now, I think the best would be install a VM with windows, but windows is so expensive. The other opition would be study without packet tracer.
Thanks for helping.
Don't give up yet!!!
It may take a little work but I PROMISE that it is worth it! You will undoubtedly want to get this going as you progress in your studies!