There is a great KnowledgeBase article that discusses using the parallel port in LabVIEW located at:
http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/c80752c53094c296862565f3007ac765?OpenDocument
I found this document by going to www.ni.com, clicking on the KnowledgeBase link, and searching for "parallel port pin."