First of all, I am going to assume that by "PC software", you mean Windows software. This being the case, there are a few ways that you can get PC software to run on a Mac. If you have one of the none Intel based iMacs, the you basically have only one option. That is to install an emulator. The best known emulator is Microsoft VirtualPC (http://tinyurl.com/k10m). Emulators create a software simulation of a PC that runs within the Mac OS. Once you have the emulator itself installed, you then have to install an OS. In this case, that would be some version of Windows. Now, there something to note about this. Since the OS is running inside of a simulation of a PC which in turn is running on a Mac, there is a huge hit on performance. If what you want to run is a program that is processor intensive (e.g. high-end real-time games, graphics programs, etc.) then you will probably find that the program runs too slowly. On the other hand, if you have one of the new Intel based iMac, you have a couple of options. The first is called Boot Camp (http://www.apple.com/macosx/bootcamp/). This is a program (provided by Apple) that lets you set up Intel based Mac so that they can boot into Window XP Service Pack 2. The other option is Parallels Workstation (http://tinyurl.com/nox8l). This is a program that allows you to run Windows side-by-side with Mac OS X. Both of these options allow you to run Windows natively on an Intel based Mac. Because of this, programs run about as fast as they would on actual PCs. Boot Camp provides all of the drivers needed to get the most out of the Mac hardware when running in Windows, but you can only have one of the OS's running at a time. So, you are either in Windows or you are in Mac OS X, not both at once. Parallels, on the other hand, can run just about any OS that will run on a PC and allows you to run them beside the Mac OS. So, you don't have to reboot to switch between OS's. However, it apparently lacks the drivers needed to access the Mac's video card. Therefore, graphics intensive program are not going to perform very well. (Don't expect to pay Windows games with Parallels.) So, those are the options for running Windows applications on a Mac. Notice the common thread to all of the options. You have to have some way to run Windows on the the Mac. The vast majority software is OS specific. That is it will only run under the operating system for which it is written. Because of this Mac software will only run under the Mac OS. The same is true of Windows software. Many programs come in both Mac and Windows versions, but each version will only run under the OS for which it is written. So, short of getting some way to run Windows on your iMac, there is no way to run your Windows program on it.