Hello, I consider switching from XNA to Tao but I cannot find the NeHe tutorials that use the Tao framework. I must be overloking it...

Tao provides access to OpenGL for managed languages (C#, Boo, etc.)

NeHe provides OpenGL tutorials in various languages (C by default with various ports).

If a specific tutorial is not available for C# (or your .NET language of choice), it shouldn't matter much, the OpenGL principles remain the same.

There are ports of NeHe to TAO here:
http://www.taoframework.com/gallery/taoopengl/nehe

Hope that helps ;)