To check if your Mac is running Snow Leopard, follow the ensuing steps:
1. Click on the Apple icon in the top-left of your screen and select About This Mac. If the version has 10.6 or higher in it, you're running Snow Leopard or later and can install the tools that we'll be using.
2. If your version is less than 10.6, we can see whether you're able to upgrade by checking that your processor has Intel in it, from About This Mac. Here we can see the OS version is 10.7.1, that is, higher than 10.6, and so, compatible with iAd Producer:
The About This Mac screen tells you the technical specification of your Mac and the operating system it is using.
If you don't have an Intel processor, and the About This Mac screen shows your processor as PowerPC, unfortunately, you can't upgrade to Snow Leopard; it's time for a well-earned new machine!