What is Vertex and Pixel shaders?
A Pixel Shader is a GPU (Graphic Processing Unit) component that can be programmed to operate on a per pixel basis and take care of stuff like lighting and bump mapping. A Vertex Shader is also GPU component and is also programmed using a specific assembly-like language, like pixel shaders, but are oriented to the scene geometry and can do things like adding cartoony silhouette edges to objects, etc. Neither is better than the other, they each have their specific uses. Most modern graphic cards supporting DirectX 9 or better include these capabilities. There are multiple resources on the web for gaining a better understand of how to use these things. NVidia and ATI especially are good resources for documents on this topic.
