If you really just need a super simple camera that follows only along X (once you move past parenting), this will do it for you, and is easy to grow from.
var player : GameObject;
var depthOffset = -10;
var verticalOffset = 0;
function Update () {
transform.position.z = depthOffset;
transform.position.y = verticalOffset;
transform.position.x = player.transform.position.x;
}
Drag the player character onto the Player variable in the Inspector, and it'll just work. Adjust your offset parameters as needed.