I'm giving away content on my site in exchange for links, and I need a way to verify a person has linked to my site BEFORE I give them access to the content. Fairly simple script. I would want it to simply verify the link by visiting the site that they type into a field, checking to see if the link to my site is really active, and then redirecting them to a page (that I will be able to define) that gives them access to the content. If the script finds that the link to my site IS NOT active, then they will be redirected to another page (that I will again be able to define).
I need this done fairly quickly. Please don't bid unless you have extensive experience with such a project.