OS X Installer has an option that describes the pending installation

macosxhints - Preview all files that Apple Installers will install: " It may just be me, but I just noticed that the installer has a 'Show Files' option in the 'File' menu that, when selected, shows all the files and where they'll be installed. This appears to only be enabled when you're in the 'Installation Type' step. Very handy to pre-examine what'll be installed. "