Not sure about any similar Address Book scripts for iPhoto ... what version of iPhoto do you have?
There are/is 3rd party solutions and i once downloaded one (can't recall it's name) but then chickened out and uninstalled it as seeing that the iPhoto Library is soooo complex I wasn't going to mess with it by running any 3rd party app in case it caused irreparable damage.
I value my photos too much and if I was to go through and delete an possible duplicate
(remember iPhoto keeps the original intact and applies any edits/changes you make to a copy), then I would break my library down
(if it was a humungous size) by creating smaller ones using the keyboard shortcut: hold Option as you launch iPhoto and choose "Create Library", I'd create as many libraries as necessary and work through them, weeding out any duplicates.
By 'weeding' I mean this isn't a simple process. You're dealing with
(possibly) priceless/irreplaceable memories here, so you have to be perfectly sure in your head about the process you employ to do this.
Do you manage your photos externally, either on an ext drive or in your own folder hierarchy? Or do you have the option checked in iPhoto Prefs to have a copy added to the iPhoto Library on import? If you have chosen the latter option then any of your photos that are outside the iPhoto Library hierarchy/structure are then considered *duplicates* and you could make a decision about whether they are taking up valuable disc space and could be deleted or not, it's your choice.
One final word is that you could export your library to a folder on the desktop
( bear in mind that if your library is very large this process could bog down your System so consider exporting the library in batches )
After export you could go through and sort it all out that way.
Whatever you do, if you decide to do it yourself as opposed to using a 3rd party solution, then it's not going to be easy or fast, of course it depends on the size of your library.
Sometimes it's good to start again ... it's a frame of mind.
There's a big chance that someone will chime in with a super effective solution that will solve your question is a few simple steps ... let's hope
