PHP Web Services Without SOAP
Subject:   Very interesting
Date:   2003-11-05 22:00:28
From:   trachtenberga
Response to: Very interesting

Yup! All you need to do is parse the input and print out some XML.

The key is publishing an API that people can depend on. I know Amazon's gone through three iterations of theirs, but they've always associated a new version with a slightly changed URL. So people can tell them apart and update accordingly.