Dave Dash has posted a quick script to help with an integration of openID into your application - well, really just to read the response back easily.
I'm working on implementing openID for reviewsby.us and for use in symfony apps. One thing I was having trouble with was parsing key value pairs, which is one of the requirements to reading responses. It's a fairly easy task, but [PHP] offers so many ways to do this.
He notes the spec for how the results are returned and shares his code (based around a regular expression) that goes through the response and separates things out into key/value pairs automatically.