For a recent REST web service project, Lorna Mitchell had to put together a server for the remote clients to use. She started with a GET request then moved to handling a POST request then to a PUT request - that's where the difficulty came in:
PHP doesn't have a built-in way to do this, and at first I was a little confused as to how I could reach this information. It turns out that this can be read from the incoming stream to PHP, php://input.
Pulling from that stream gave her the raw data she needed (nicely urlencoded too) that she could parse out and use. She includes a simple example that has a check for the REQUEST_TYPE in the _SERVER superglobal to see how the request should be handled (PUT versus GET).