As long as this is an unfiltered portal, the number of portal rows and the number of related records are the same. Then you can define a calculation field in the parent table that counts your related records to give you the total number of portal rows:
Count ( portalTable::FIeldThatisNeverEmpty )
Since the match field used in the portal relationship cannot be empty or the record wouldn't appear in the portal, this method usually "counts" the portal's match field.
Thanks again phil.. you are the best tutorial!.... thumbs up!