Hi Adam,
The contacts API contains a series of URI endpoints that may be called from any language. For instance, in PHP 5 you may make an OAuth signed request to the endpoints to capture the data. If you're looking for an implementation SDK I would take a look at our PHP SDK:
http://developer.yahoo.com/social/sdk/If there's something specific which you are trying to do, or the exact error that you are seeing on your server, please let us know and we'll do what we can to help.
Jonathan LeBlanc
Senior Software Engineer
Yahoo! Developer Network
Twitter:
jcleblancIs there some form of the Yahoo Contacts API (Not the Yahoo Address Book API) that is written with PHP5 in mind, because in it's current form it refuses to work on my PHP5 server.