Labels using shape index

[Eric Shuman]

I'm new to mapserver and am still trying to keep my head above water so
maybe this is very simple, but I have not been able to find a solution so
far...

I have gotten as far as creating a map file, and PHP mapscript that will
query a shapefile by feature and return a map.  I would like to label the
returned features with the index number of the shapes. (ie. 0, 1, 2...)  I
have only been able to get labels from the shapefile attributes themselves
to work.

Is there a way to define the LABELITEM as the ID or shapeindex of the
returned features?

Do I need to create an annotation layer with points for each shape and
define a label value? How???

Can you add a field to the returned featureQuery and calculate the field to
be used as the LABELITEM?

Suggestions, examples, and guidance would be greatly appreciated!  Thanks in
advance.

~Eric