http://www.prepaid-wiki.de/index.php5?title=Hauptseite
In German, but seems to be a good source for the ever-expanding German prepaid market.
Stan
Phones: DASH V3 (3)
Service: US T-MO post paid (2) - US T-MO prepaid (2) - UM+ - TravelSIM DE SIMYO - DE SUNSIM T-Mobile DE
Calling Cards: Onesuite Enjoyprepaid AT&T MCI Mobivox