Recently somebody asked me for help getting PowerBuilder.Net (and eventually PowerBuilder Classic through a COM Callable Wrapper) to interface with Google Calendar. That actually turned out to be fairly simple because Google provides a .Net library for Google Data API which provides access not only to Google Calendar, but to a number of other Google services as well, such as Blogger, Contacts, Picasa Web Albums, Spreadsheets and YouTube.
We're going to see just how easy by accessing Google Calendar and retrieving our events for the next few days. To do that, first download and install the Google Data API .net libraries (you only need the first one on the list). Then create a PowerBuilder.Net WPF project and add references to the Google.GData.AccessControl, Google.GData.Calendar, Google.GData.Client and Google.GData.Extensions assemblies.