Free Web Site Link Exchange Software

I've been looking this evening for a free PHP reciprocal link exchange package. I'm prepared to roll my own if I can't find what I'm after but there's so many of us hacking code these days that I can't imagine that someone's not already done so. Can anyone recommend such a package? I'm looking for the following features (in no particular order): mySql back-end admin interface user interface for others to submit link ability to allow link to be automatically added or approval required reciprocal link check - spider, etc. submitters site dead link clean-up/removal allow definition of multiple categories flexibility ... I'm not looking to create a link farm but rather to add content to my wife's web site. She often receives requests from others related to her field to add reciprocal links. Many thanks. -- Regards, Scott Dudley