One of the very cool Google products is the AdSense API service designed for developers and owners of wiki/blog/user-contributed-content farms and hosting services. Read more about it here: http://code.google.com/apis/adsense
At some point I have decided to create my own lightweight PHP5 library to communicate with AdSense API. Google seems to encourage people to use NuSoap — which has the benefit of being PHP4-compatible, but does not use benefits of (IMHO great) PHP5 Soap functionality.
My implementation is quite light. It will work on PHP 5.x only and uses WSDL to automatically generate client objects.
The code from below is used in the AdSense API implementation at Wikidot.com and works nicely.
/* asd */