|Go to the App Store. Get XCode. Simple.|
The other compilers that you mention, being for Windows, aren't going to work on your Mac.
Edit: On second thoughts. you might have problems with the App Store version as you are on an old version of OS X. In that case you'll need to download an older version.
Here's a link to the various versions of Xcode: https://developer.apple.com/downloa...
You need to log on with an Apple Developer ID, but you can get a free one that allows this level of access. I think that 3.2.6 is the highest version that will run on Snow Leopard.