This is another article that I wanted to write long time ago and now that I discovered how to get a service from a Visual Studio add-in and the Data Design Extensibility (DDEX) SDK, I have written it today. It is a question that keeps appearing in the forums:
HOWTO: Get data sources, data providers and data connections from a Visual Studio 2005 add-in
http://www.mztools.com/articles/2007/MZ018.htm
It’s great to see you that you covering some of these areas! Data providers is a common topic that comes up with Visual Studio extenders!