HTTP-GET-to-HTTP-POST proxy

Question

Hey.

I'm writing a Yahoo Pipe that requires communication with a specific web service. Unfortunately, the web service only accepts POST, and the Yahoo Pipes Web Service JSON POST module issues the POST in the wrong format.

So ideally, there would be some proxy somewhere on the internet that accepts a GET, takes some parameters, and converts that to a POST, then returns the results. Any ideas if something like this exists?

Thanks.