Alpha blending in DirectDraw

The easiest way is to use Direct3D for 2D purposes. Most tutorials dealing with Direct3D are based on 3D (makes sense), so I had to find out myself how to use Direct3D, and here are the results:

Direct3D -> 2D: Rotation
Direct3D -> 2D: Fake lighting
Direct3D -> 2D: Alpha Blending, and an easier and faster way to fake lighting

All these samples use the easiest form of Direct3D, without real lighting or matrices.

I hope they're of some use to you!