Something

using System;
using Server;
using Server.Items;
using Server.Targeting;
using Server.Mobiles;

namespace Server.Items
{
    public class Headpost : Item
    {
        [Constructable]
        public Headpost()
            : base(0x1296)
        {
            Name = "Headpost";

            //You had Movable with a small m
            Movable = false;
        }

        public Headpost(Serial serial)
            : base(serial)
        {
        }

        public override void Serialize(GenericWriter writer)
        {
            base.Serialize(writer);

            writer.Write((int)0);
        }

        public override void Deserialize(GenericReader reader)
        {
            base.Deserialize(reader);

            int version = reader.ReadInt();

        }

        public override void OnDoubleClick(Mobile from)
        {
            //You are not supposed to send the mobile as a target parament, but the headpost. We do this with the "this" keyword
            //from.Target = new HeadpostTarget(from);

            from.Target = new HeadpostTarget(this);
        }


        private class HeadpostTarget : Target
        {
            public Headpost m_Post;

            public HeadpostTarget(Headpost post)
                : base(3, false, TargetFlags.None)
            {
                //m.SendMessage("Target a head.");
                m_Post = post;
            }

            //You had the wrong paraments for OnTarget, will be fixed with intellisence
            //protected override void OnTarget(Item m)
            protected override void  OnTarget(Mobile from, object targeted)
            {
				Head head;
				if (target is Head)
				head = target as Headl;
				else
				{
				from.SendMessage("That is not a head");
				return;
				}

                Point3D headLocation = m_Post.Location;
                headLocation.Z += 18;
				head.MoveToWorld(headLocation);
                //The head instaces doesnt exist yet, how will you get it?
                //head.MoveToWorld(headLocation);
            }
        }

    }
}