An enterprising developer has wrapped the AdWords API in PHP, and is selling the library. Ostensibly it should make using the Google AdWords API a lot easier. Is it worth it? Oddly enough, I think PHP is one of the few languages where it's already easy enough to use the Google API.
A library for VB might be useful, however. Microsoft has made all the modern SOAP tools work well for VB.NET. Unfortunately, 80% of the world still uses Visual Basic 6 - and it's much harder to get VB6 to work with the Google AdWords API.