It is not currently possible to link two instances of Family Tree Maker to the same tree on Ancestry.com. You can use FTM on your Mac at home, and use Ancestry.com with your web browser on the 2nd computer.
It is possible to use the iPhone/iPad app on a given tree along with FTM, so the example on one of the earlier replies is valid - just not possible to do two computers (Mac and/or Windows).
It is possible to use the iPhone/iPad app on a given tree along with FTM, so the example on one of the earlier replies is valid - just not possible to do two computers (Mac and/or Windows).