Create a Central PayPal IPN

I'm needing a job done where it involves creating a central PayPal IPN. For anyone who has done this, they will know it's not so hard to do. So you would have to have done this before. I also have a template script to use so this will make this project much easier. If possible, if you can provide some proof of an existing job you've done, this will be great, since it's an important job.