Virtual Machines
Hi Wind-Dance,
posters are telling you about virtual machines or "emulators" is an old fashioned name for them. They are programs that simulate a typical PC on your intel based mac. They typically require large amounts of RAM. 1 or 2 gigabytes if you can manage it.
Once you install the VM software (two I recommend are Fusion from VM Ware or Parallels Desktop from Parallels). Then you need to start your emulator and install the Guest Operating System. In your case, that would be Windows XP, I am guessing. You can Install Windows 98 or Windows 2000, or Windows Vista.... Which one to choose depends on your astrology program.
Then! Once you have the VM software installed and the Guest Operating System (windows xp) installed, you can install your astrology program.
You will be able to install any windows program at that point.
The VM software uses the various peripherals on your mac in the Virtual Machine (windows xp, for example) - In the case of the Internet, the PC in your virtual machine appears to be connected to the network your mac is connected to. The keyboard and mouse are used by the guest machine. The DVD drive is used by the virtual machine, the usb ports pass through to the VM and the hard drive of the VM is a file located on the Mac.
Both VM Ware and Parallels have free try-before-you-buy versions you can download. VM Ware is at vmware.com and parallels is at parallels.com