To save your custom theme so it appears in the Shopping Cart Creator Theme window on another computer, first make a copy of your theme. To do this, go to the location on your computer where your theme is stored:
Windows XP
C:\Documents and Settings\{username}\My Documents\CoffeeCup Software\Shopping Cart\Themes\My Themes
Windows Vista and Windows 7
C:\Users\{username}\Documents\CoffeeCup Software\Shopping Cart\Themes\My Themes
Next, copy the theme to the same location on the other computer. When you start Shopping Cart Creator, it will be listed in the Themes tab.