Here are some links on POCO and OAuth

PoCo / OAuth
==========

http://portablecontacts.net/draft-spec.html

http://blog.charlvn.com/2008/11/google-contacts-api-with-zend-framework.html

http://sites.google.com/site/oauthgoog/Overlap

http://code.google.com/apis/accounts/docs/AuthForWebApps.html

http://blog.adsdevshop.com/2008/04/18/import-gmail-contacts-using-ruby-on-rails/

http://developer.yahoo.com/oauth/

http://oauth.net/code/

http://developer.yahoo.com/oauth/guide/oauth-libraries.html

http://oauth.googlecode.com/svn/code/php/example/echo_api.php

http://oauth.net/documentation/getting-started

http://portablecontacts.net/

http://googlesocialweb.blogspot.com/2009/03/take-your-google-contacts-with-you.html

http://googlecodesamples.com/oauth_playground/

http://code.google.com/apis/accounts/docs/OAuth.html

poco