Link:

http://googlesystem.blogspot.com/2010/03/browse-newspapers-in-google-news.html

So, search was available before (http://blogoscoped.com/archive/2008-09-08-n66.html) and now the new feature is that you can browse page by page, or ...?

The original source post says that new feature is "Browse this newspaper" link, described as
"If you go to the Google News Archives and find a digitized back issue from the Google archives, you should be able to now browse that newspaper directly on Google."
with a screenshot.

Philipp you can now browse a newspaper by release edition date. As long I go on this tool (see http://blogoscoped.com/forum/168583.html) I can confirm that this is new.