Double sided rendering meshes?

Anyone know how to have 2-face rendering for meshes?

You Need to Write One line in a shader. So in Case you use the unity ones, you Need to Open them in your texteditor (somewhere on the unity Website were editable shaderversions for Download. ) bevor the Passes you Need to Write something like backface = true. Unfortunatly i forgot the Command Name. Could Be double, doubleface, back or the like.