Googleads PHP SDK makes it easier for developers to build native app elements for AdWords API and DoubleClick for Publishers API. The SDK supports PHP version 5.3 and above, and works with SoapClient, OpenSSL and cURL extensions. It simplifies the storage of developers’ authentication credentials and supports the creation of web service clients on SOAP-based API platforms in addition to carrying the example code for launching the integration of target APIs.
The Sklik PHP SDK by Michal Kuchta allows API interaction to access search advertising features. Library and examples available, in addition to a tutorial at https://github.com/niximor/php-sklik/blob/master/sklik_tutorial.php