Searching remote web sites for content

I have a web site and google likes to count the inbound links. I have set up a way for people to add links from my site to theirs, however I would like to check whether they have linked back to my site. I ask them to nominate where the link back page is, and I could check this manually. But is there a way to check whether the remote page links back using a php script, so that I could get a report and follow up on exceptions, without having to check all pages that say they link to my site? John