Help creating Shader wich changes the opacity

Hello guys
I never developed a shader before, and I need a shader wich changes the opacity of the renderer depending on distance.
I have a long plane, which has a solid white texture, and it gets saturated from the material.color.
I want that the plane get transperancy gradiently when the camera is so close.
So this plane has 100% of opacity where the camera is far, and 0% of opacity where the camera is near.
How can I do this? Please help, thanks.

I think you should post your question in this forum: http://forum.unity3d.com/forums/31-Commercial-Work

I am not asking to create a shader for me, I only asked how to? any reference? any explanation?
Unity Reference is too strange to learn, they used a strange english, or it may be to me, because I am an european. Any way thanks.

http://en.wikibooks.org/wiki/Cg_Programming

Thanks, I am going to learn it.

http://wiki.unity3d.com/index.php?title=AlphaClipsafe