I have found a very useful little tool that allows converting data (schema/instaces) to and from .N3, N-Triples, RDF/XML and OWL. This utility is particularly handy when your RDF stores accepts schemas in particular format only (in majority of cases N3/N-Triples). Here is the link to the tool and syntax which allows you to do so ( It took me sometime to find the exact syntax so I hope it will save some of your time).
http://www.w3.org/2000/10/swap/doc/cwm.html
&
http://infomesh.net/2001/cwm/
syntax to convert from RDF/OWL to N3.
python cwm.py --rdf file-to-be-converted.owl --n3 > file-as-output.n3
or even better....
you can use Protege :)
Open .owl file in protege and go to File -> SaveAs and save it as .N3 or turtle. So easy, isnt it?