Useful Links:
http://www.bahn.de German train network
http://www.vrr.de/ Regional train network for NRW
http://www.muensterland-tarif.de/ Another regional train network for NRW
http://www.nordwestbahn.de/ NordWestBahn site for Niedersachsen
http://www.hist-stadt.nrw.de/index.php Historische Stadt- & Ortskerne in Nordrhein-Westfalen. A great site also promoting small towns!