Portable Contacts for PHP?

I see that Google is implementing the Portable Contacts API for developers to get the user's contacts. This is similar to what I want to do, and I especially like the fact that the protocol is open, and through it I can support more than just Google.

What I would like to know is if there is a library for PHP that implements this protocol, since I don't feel like writing from scratch / reinventing the wheel.

I wouldn't post questions like this at all that could be answered simply by googling, but I've done my search on this and can't find any relevant information.

By the way, I'm not using Zend, so please don't suggest this to me unless it is possible.