Stop axis movement?

Is there anyway, through scripting, to have an object's x axis position stay the same, no matter how much its parent moves?

http://forum.unity3d.com/threads/21765-Restricting-z-axis

http://www.google.com/search?client=opera&rls=en&q=disable+axis+movement+in+unity3d&sourceid=opera&ie=utf-8&oe=utf-8&channel=suggest

Third choice looks promising, but yeah.

Good luck! =).