Using part of a field as a label

[David L. Kriske]

I am trying to label Tiger-derived street data (ESRI Streetmap 2000) and
include highway shields for Interstates and other major highways using
symbols and annotation layers.  My problem is that the name
field in the Tiger database for interstates is characterized as "I-5" or
"Hwy 101" when the label on the map I would like to include is only "5" or
"101".  Has anyone ever tried to add hwy shields to Tiger data using this
field and if so is there a good way to do this other than manually adding
a new attribute containing only the numbered portion of the name?  I am
using the ENTIRE US as my domain so editing these large shapefiles (one
for each state!) is very time consuming, especially since shapefiles
don't take kindly to editing their associated dbf file outside ARCVIEW.

David