What is the easiest hack to change Options-Gallery-Website URL depending on the language chosen? Should I change the function or just hard-code it in the theme? I'm guessing changing the theme would work better with upgrades.

Thanks.

I think you answered yourself..;-)

Good, Just needed reassurance some better method wasn't out there

Does Zenphoto have a method of overriding php functions from the core in functions.php in the theme? Just checking as that would be easier than hardcoding in each php file of the theme, which then makes it harder to duplicate the theme in another site.

You cannot override (which means re-declaring) existing php functions by design of PHP. If you need specific functionality you need to create theme custom functions (all explained on the theming tutorial) or a custom plugin.