If you are interested in the Dutch medium wave pirates a good site to check out is Wizard's medium wave free radio blog, where he regularly posts logs, recordings and other interesting material. I'm always impressed with his success at pulling in the signals from the Netherlands.
In a recent posting he mentioned he also has a YouTube page where you can listen to some of his catches. The address is http://www.youtube.com/mwpiratereview
His blog can be found at: http://mwfreeradio.blogspot.co.uk/