source for ebooks

Dear /book/,

this is my first time post here. so, I don't quite know where to get good and rather new ebooks for my sony reader, which I bought last month. Could you give me a hint please? German ebooks would be great, too.

I guess by "get" you mean "pirate", otherwise you're pretty dumb.
So, then:
http://www.anonib.com/bookchan/
undernet #bookz - if you're a total dcc newb read some tutorials instead of fagging up the channel.

Should be enough for you, although you'll probably have to stick to PDF, as I don't think there will be many books in EPUB format.
Also, I have no idea if there are German books to be found there because despite being a Kraut myself I have honestly only looked for English ones.