c# home seems to be a fairly new c# web site. They currently have 4 managed DirectX tutorials:

• Intro to DirectX 9. Device setup, matrix math and texture examples.
• DirectX 9 Tutorial. Device setup and enumeration, determining caps
• DirectX in c#. Covers COM interop to DirectX as well as managed code. Has some performance numbers too.
• DXSound part 1. How to play 3d sound from managed code.