   Use DirectX 9 and Direct 10
  I am making a game engine but want to make games that can support both directX 9 and DirectX 10 because some users wont have directX 10.  Can you point me to some tutorials if you can or just give me a basic answer.Thanks   
  a) opengl ;)b) just look at the d3d9 and d3d10 tutorials. depending on the users choice create a renderer with the api they choose.c) look in to interfaces. build a rendering interface and 'map' it to the api of choice. tutorials somewhere here on gd.net, just browse a bit.   