While pursing this [http://wiki.blender.org/index.php/Manual/Soft_Bodies] page on the blender site, I came across the section titled [Swing]. Hey this sounds neat I thought however the instructions are not very clear there and I could not seem to get them to work as written.
Not being deterred I decided to see if I could figure this out. Here is the result.

[note] I am using blender 2.48, to ensure things appear in the right orientation, go to the user preferences panel under edit methods make sure 'Switch to Edit Mode' and 'Aligned to View' are selected.

Delete the default cube/plane and switch to the front view. [Numpad 1] Add a plane, it will appear with all the vertices selected. Deselect them [A]. Select the bottom two vertices and delete them. You now will have a plane with two vertices connected with an edge.

Select the left most vertex press [f9] to get to the object editing buttons. Make a new vertex group, call it 'Anchor', set the Weight to 1.0, and click 'Assign'. Select the right vertex, make a new group, call it 'Target' with a 'Weight' of 0. click 'Assign'.

Now switch to the object editing panel [f7] and bring up the physics sub panel [f7 again]. Click on the 'Soft Body' button to enable the soft bodies. Set the 'Goal' value to 0 [to the right of the Use Goal button]. Then click the little up/down arrow thing to the right of the 'Use Goal' and choose the 'Anchor' Vertex group. If you animate now [ctrl-a] you will notice a nice swinging action.

Now lets make use of that action. Add an empty, Go to the Object button panel [f7] and we want to add a child of constraint to the empty as a child of the plane. Parent OB:<your plane>, VG: Target. Now when you animate you'll see that the empty follows the swinging plane nicely. This will work with other objects to get them to follow the soft body physics. If the child object is offset and you want it on the swinging vertex, clear the location and it will snap to the vertex [alt-G].

Here is a quick video of the end result.