Rendering

In my engine I am developing I have got quite a lot of the logic part finished and so I need to start thinking about how I am going to do the rendering. I have heard that I should be using Vertex buffers for speed so what are Index buffers? Also how would I use a vertex buffer for an object ie drawing it all i could call DrawPrimitive(...) on it as obviously there will be different textures on it so i would have to change the texture each time there is a poly with a different texture. ========================== It compiles.... Ship it!!! ==========================