Practically all Nazi flying saucers were made up in the 1960s. The 1970s German magazine
Luftfahrt International even devoted an article to it, with the intention to break the myth. However there are still lots of people that believe in BMW Flügelrads and whatnot...
As far as I'm aware the only flying disc ever made in Germany during WW2 was the Arthur-Sack As 6 V1. A most peculiar aircraft. Thanks to its weak undecarriage it never managed to take off and everytime stranded halfway its take-off run.
More info:
http://www.luft46.com/misc/sackas6.html
PS. I've made a 3D model of the As 6 V1 but unfortunately haven't been able to finish it yet:
http://home.wanadoo.nl/r.j.o/skyraider/as6v1_1wip.htm