If you have the Apple XCode Tools installed on your Mac, you can follow the guidelines for Linux (Other distributions, manual installation) for setting up your development environment. The only difference is that you have to install wxMac instead of wxGTK. Instructions for installing OpenCV on Mac are available from [Willow Garage].
SwisTrack should compile within XCode (use code/AppleXCode/SwisTrack.xcodeproj on the SVN tree) and through the make build system ("Makefile"). You can create the application with "make osxbundle" run in the directory /Code/gui.