How to install iphone themes on mac using i-FunBox application, you need to have a jailbroken idevice if it is, then proceed to step one, if not there are plenty of guides on the web, I prefer iClarified they are simple, very specific and update regularly.
Download i-FunBox (it's free) for mac connect you idevice to computer via usb cable.
Select from the navigation bar on the left raw file system then go to private/var/stash/Themes.xxxxx for WinterBoard themes or go to private/var/mobile/Library/DreamBoard for DreamBoard themes
Select the theme file xxxx.theme and drag it to private/var/stash/Themes.xxxxx for WinterBoard or for DreamBoard themes drag the file to private/var/mobile/Library/DreamBoard.
Go to WinterBoard app on your iphone and select the new theme you just install and respring.
Congratulations! You just finished, enjoy your new theme.