Hello I am owed almost $21000 from a personal loan I made with this person. We were under written contract signed by both parties, I worked with him and considered him a friend. Not so . Loan is 5 years old. He did repay $4k of it two yrs ago. He lives in PA and works in NY making upwards of $80k, he does have 5 kids two of which are handicapped. I have called spoke with him and I do not believe he is ever going to pay anything further . Can someone tell me what recourse I might have. I imagine I need to start by taking him to court IN PA first and if judgement is awarded then pursue wage garnishment. He likely has little if any $ in bank , since home was bought for $350k and is worth maybe $200 and he is bringing up 5 kids... Another idiot for the 1.5% interest debacle some 7 years ago.
Does PA or is it NY permit wage garnishment of wages

NY definitely does. I believe PA does also. And, yes you need to first obtain a judgment which shouldn't be too hard since you have a signed contract.

... He lives in PA and works in NY making upwards of $80k, ... I imagine I need to start by taking him to court IN PA first ...

You could sue him in New York, if you can serve him with process there. Or, if you sue him in Pennsylvania, you would have to register the judgment in New York before you can garnish his wages there.

It's probably above the small claims (http://www.lawny.org/index.php/consumer/small-claims-court-self-help-115) limit, so any restrictions to the state of his residence wouldn't apply.