Tableau is currently unavailable on Macs. In order to use Tableau if you have a Mac there are 3 main options:
1) use ITS's Virtual Lab service. Connect via web to their Windows imaged machines, and use Tableau. ITS runs the “Virtual Lab” service whereby students can connect to a Windows desktop from anywhere. It’s very similar to Remote Desktop. When they connect, they basically see the Windows computer running the wide range of applications that are typically found on campus lab computers. However, this is a static image, so no installation and re-use of software is possible here. More information on this service can be found here: http://help.unc.edu/CCM3_031721 . UPDATE 9/5/2012: ITS has upgraded its “Virtual Lab” service to be even easier to use. Applications offered in the physical computer labs are now easily accessed through the web. This can be a good resource for you or your students. For details and a full list of available applications, please visit http://sils.unc.edu/it-services/remote-access/its-virtual-lab
2) install virtualization software on your Mac to emulate Windows environment. This can be something like Parallels (approx. $70), Bootcamp (with Mac OS X), VMWare or Virtual Box. SILS IT staff has had good experiences with Virtual Box and it is free. More info here: https://www.virtualbox.org/
3) There are two PCs in SILS Lab with Tableau installed for our use. PC-49 (in the collaboratory space), and pc-48 (the system in the far right row against the wall).