Syndicating Affiliate Stores?

[sigh] My new client took a liking to this idea of syndicating her wedding supply store on her affiliates' sites like this one:
http://www.photoshop-stuff.com/TemplateMonster.html

Does anyone have any idea how this is done? Is there a commercial script that generates the affiliate link? Then it seems to be pulled into an iframe on the affiliate's site when they plug in the php code.

Any help would be appreciated. She is quite excited about this concept and wants to start right away. I've been surfin' the net for two hours without luck of finding a script that will do it. At this point, I don't think price matters to her. Thanks.