Hello,
Sorry, I don't speak German so I post in English.
I developed an application for iPhone and iPad to read Japanese (Web or text file) while having a dictionary to quickly find the meaning of an unknown word.
I originally developed this application because I thought I did not read enough Japanese because of the pain of having to constantly lookup in the dictionary for unknow words. So, my level had dropped significantly after the passage of JPLT.
Now, using this app, I read Japanese on my iPad every day and I really enriched my vocabulary. (Of course, I may have a biased opinion because I'm the developer of the application: D).
The application is called Wakaru and runs on iPhone and iPad.
There is a video on youtube
http://www.youtube.com/user/WakaruApp to get an idea and a
site that details the features.
Sorry to pollute the topic with * commercial * post in English, but I really think Wakaru may be useful to anyone wishing to advance in Japanese.
The direct link to the
AppStore.