Here is something basic for you to start with. This one works on the car(selectedSet()) but you can adjust it to work on all selected items, or write some code using enterPoint or enterLine type commands to selecting the shapes to label.
procedure(myLabelSelectedShapeByNetName()
let((shp netName lbl )
shp = car(selectedSet())
when(netName = shp~>net~>name
lbl = dbCreateLabel(
shp~>cellView
"text"
car(shp~>points)||shp~>beginPt||car(shp~>bBox)
netName
"centerCenter"
"R0"
"roman"
shp~>width||1.0
)
lbl~>parent=shp
)
) ;let
) ;proc
Derek