A description of OWLS2PNML is reported in the paper:

A. Brogi, S. Corfini, S. Iardella. From OWL-S descriptions to Petri nets. In Service-Oriented Computing ICSOC 2007 Workshops - Third international workshop on engineering service-oriented applications: analysis, design and composition (WESOA’07), Wien, Austria, September 17, 2007. LNCS 4907, pages 427-438. Springer.

The OWLS2PNML jsp application can be dowloaded here.

A set of OWL-S service descriptions (process models) is availble here.