subtitles and download.
One reviewer from Finnland wrote
"The only real problem as I am writing this is that it seems to be impossible to get one's hands on non-German language versions (I mean subtitled, not dubbed, which should be defined a crime against humanity). However, if you speak even tourist Deutsch, have a look at this series. You cannot lose more than a few euros and six times fifteen minutes of your time."
I think this is complicated to achieve, since Ijon and the Alians speak with a funny east-european (polish?) accent, with a lot of wordplays. I don't think it's easy to find a translator who can map this to English.
Even me from time to time I'd like to have German subtitles, just to understand whats going on.
BTW: you don't need to buy the DVD, the complete series is free for download:
http://www.zdf.de/ZDFde/inhalt/25/0,1872,5244377,00.html look out for mediathek in the upper right corner.