Okay, here's what you'll need to do:
1. download and install VMware Fusion (you'll have to register for the 30-day eval. if you don't want to buy it):
http://www.vmware.com/download/fusion/eval.html
2. download a Linux disk image (.iso) (I recommend Ubuntu):
http://www.ubuntu.com/ (click download, and stick with the default options)
3. open VMware Fusion and click "new"; as you're going through the set up wizard, make sure you select "Linux" for operating system and "ubuntu" for version; also, when you get to the last screen of the set up wizard, make sure you select "use operating system installation disk image file" and then specify the location of the Ubuntu image you downloaded.
4. Run the virtual machine, and select "start or install ubuntu" on the main screen. This will start Ubuntu in the virtual machine. When you get to the Ubuntu desktop, click "install" and go through the installation wizard.
5. Once you've installed Ubuntu in the virtual machine, go to "Virtual Machine" ==> settings ==> CD/DVD ==> and make sure "automatically detect physical cd/dvd drive" is selected.
6. Go back to "Virtual Machine" in the menu bar and select "install VMware tools". This should mount a disk on your Ubuntu desktop.
7. In Ubuntu, go to Applications ==> Accessories ==> Terminal. In terminal, type (or copy/paste) the following commands:
cd vmware*
sudo ./vmware-install.pl
That will start the VMware tools setup wizard; the default options should be fine.
8. finally, to install Internet Explorer, follow these directions:
http://www.tatanka.com.br/ies4linux/page/Installation:Ubuntu
Once you're finished, you'll be able to use all the AAMC CBT features; you'll also have Internet Explorer for the rare instances in which you might need to use it. If you need more clarification, PM me.