Head Porting basics

Thanks very much for the info Godfather, and thank you Rob R especially for the really helpful pic kinda gives me something to shoot for. What kind of bits and tools are you guys using? I know there's port and polish kits for sale in jeg's and summit or is it good enough to use some rotary file bits on a drill? Again thanks much for the info, it's appreciated and will defenantly be put to good use.