I have been following the developments in amateur radio a bit. A new digital system called d-star is making progress. I found out there is a nearby d-star repeater on the Gerbrandytoren: PI1UTR and noticed they have a radio roundtable every Tuesday evening. I don't have the digital voice equipment to listen to that via the air but these days it is easy: the roundtable uses D-star reflector 017 and there is this 'Listen to REF017A' button which links to a livestream. I copied the livestream URL to the 'Internet radio' setup of the Netgear mediaplayer and listened to the roundtable via the home sound system. Way too easy method to listen to radio amateurs! But it is a nice way to get a feeling for procedures, what is being discussed and such. Even with digital voice and a reasonable quality livestream it still takes experience in radio listening to understand everything.
I found an active nederlandse d-star website but I still can't find a good basic d-star for non-radio-amateurs explained manual. A lot of the information is either really basic or aimed at informing existing users of new developments. The english wikipedia article on D-Star has a lot on the development and technical side of D-Star but not on its use.
Update 2010-04-29: I found a lot more interesting and accessible information at the D-Star UK website.